Absorbent article

ABSTRACT

Provided is an absorbent article having a top sheet with an opening-formed area in which openings are formed, and non-opening-formed areas in which no openings are formed, said absorbent article being capable of preventing liquid from remaining on the surface of the opening-formed area of the top sheet. In the present invention, the top sheet is a resin sheet having an opening-formed area ( 12 ) in which openings are formed, and non-opening-formed areas ( 5, 14 ) in which no openings are formed. The opening-formed area ( 12 ) is disposed in an outlet-facing area ( 16 ) that faces at least an outlet for fluid from a wearer. The top sheet ( 2 ) has a blood modifier layer on the surface of at least the outlet-facing area ( 16 ). The blood modifier of the blood modifier layer has an inorganic/organic balance (IOB) of 0 to 0.60, a melting point of not more than 45° C., and an aqueous solubility of 0.05 g or less with respect to 100 g of water at 25° C.

TECHNICAL FIELD

The present invention relates to an absorbent article, such as asanitary napkin, panty liner, incontinence pad or incontinence liner.

BACKGROUND ART

Sanitary napkins that employ as top sheets perforated plastic filmshaving non-perforated sections at the side regions of the sanitarynapkin are known in the prior art (see PTL 1, for example). This canprevent body fluid that has been absorbed into the absorbent body in theside region of the sanitary napkin from passing through the holes of thetop sheet and flowing backward, causing spoiling of the flap andunderwear.

CITATION LIST Patent Literature

-   [PTL 1] Japanese Unexamined Patent Publication HEI No. 5-154176

SUMMARY OF THE INVENTION Technical Problem

With a conventional absorbent article employing as the top sheet aperforated plastic film without perforations at the sectionscorresponding to the side regions of the sanitary napkin, as describedin PTL 1, a low elimination rate of body fluid discharged by the wearer,or high viscosity of the body fluid discharged by the wearer, can resultin residue of body fluid on the surface in the region in which holes areformed in the top sheet. When such residue of body fluid is repeated,the holes of the plastic film become reduced in size by theincreased-viscosity body fluid while it is residing, such that bodyfluid that has been discharged by the wearer can no longer easily passthrough the holes, and the body fluid of the wearer thus tends to flowon the surface of the top sheet. Particularly when the top sheet hasnon-perforated sections, body fluid that has flowed from the region inwhich the holes are formed flows directly to the surface of the topsheet at those sections, without being absorbed into the holes, andtherefore body fluid of the wearer often leaks out from the edges of thesanitary napkin.

It is an object of the present invention to provide an absorbent articlewherein the top sheet has perforated regions in which openings areformed and non-perforated regions in which openings are not formed,whereby residue of body fluid on the surface of the perforated regionsof the top sheet can be inhibited even with a low elimination rate ofbody fluid discharged from the wearer and even with high viscosity ofbody fluid discharged from the wearer.

Solution to Problem

In order to solve the aforementioned problems, the invention employs thefollowing construction.

Specifically, the invention is an absorbent article having a lengthwisedirection and a widthwise direction, and comprising a top sheet providedon the skin side, a liquid-impermeable back sheet provided on theclothing side, and a liquid-retaining absorbent body provided betweenthe top sheet and the back sheet, wherein the top sheet is a resin sheethaving perforated regions in which openings are formed andnon-perforated regions in which openings are not formed, the perforatedregions being provided at least in the excretion hole-correspondingregion that corresponds to the excretion hole for body fluid of thewearer, the top sheet having a blood modifying agent layer on thesurface of at least the excretion hole-corresponding region, and theblood modifying agent in the blood modifying agent layer having an IOBof 0 to 0.60, a melting point of no higher than 45° C. and a watersolubility of no greater than 0.05 g in 100 g of water at 25° C.

Advantageous Effect of the Invention

According to the invention, with an absorbent article in which the topsheet has perforated regions in which openings are formed andnon-perforated regions in which openings are not formed, it is possibleto inhibit body fluid from residing on the surface of the perforatedregions of the top sheet.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view showing an embodiment of an absorbent article ofthe invention.

FIG. 2 is a simplified cross-sectional view showing a cross-section ofFIG. 1 along line A-A.

FIG. 3 is a diagram illustrating first protrusions, second protrusionsand bottom sections formed in the top sheet of an absorbent articleaccording to an embodiment of the invention, in the regions on the outersides of both edges in the widthwise direction of the absorbent body ofthe body section, and in the wing sections.

FIG. 4 is a diagram illustrating first protrusions, second protrusionsand bottom sections formed in an excretion hole-corresponding region ofthe top sheet of an absorbent article according to an embodiment of theinvention.

FIG. 5 is a photomicrograph of openings formed in the sides of firstprotrusions.

FIG. 6 is a diagram illustrating an embodiment of a method for producingan absorbent article according to an embodiment of the invention.

FIG. 7 is a set of illustrations of a recess-forming roll to be used forproduction of an absorbent article according to an embodiment of theinvention.

FIG. 8 is a diagram illustrating the region in which recesses are formedby a recess-forming roll in a sheet for a top sheet.

FIG. 9 is a set of illustrations of the upper roll of a stretching gearroll to be used for production of an absorbent article according to anembodiment of the invention.

FIG. 10 is a set of illustrations of the lower roll of a stretching gearroll to be used for production of an absorbent article according to anembodiment of the invention.

FIG. 11 is an illustration of a sheet for a top sheet to be stretched bya stretching gear roll.

FIG. 12 is a diagram for illustration of a top sheet as a modifiedexample of an absorbent article according to the first embodiment of theinvention.

FIG. 13 is a diagram for illustration of a top sheet as a modifiedexample of an absorbent article according to the first embodiment of theinvention.

FIG. 14 is a diagram for illustration of a modified example of anabsorbent article according to the first embodiment of the invention.

FIG. 15 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin wherein the top sheet comprises tri-C2L oilfatty acid glycerides.

FIG. 16 is a pair of photomicrographs of menstrual blood containing andnot containing a blood modifying agent.

FIG. 17 is a diagram illustrating a method of measuring surface tension.

DESCRIPTION OF EMBODIMENTS

The invention will now be described with reference to the accompanyingdrawings, with the understanding that the invention is not limited tothe examples depicted in the drawings.

FIG. 1 is plan view showing an absorbent article according to anembodiment of the invention, and FIG. 2 is a simplified cross-sectionalview showing a cross-section of FIG. 1 along line A-A. The absorbentarticle 1 comprises a body section 10, having a liquid-permeable topsheet 2 provided on the skin side (the skin-contact side), aliquid-impermeable back sheet 3 provided on the clothing side(non-skin-contact side) and a liquid-retaining absorbent body 4 providedbetween the top sheet 2 and the back sheet 3, and a pair of wingsections 5 each having a top sheet 2 and a back sheet 3, provided onboth sides of the body section 10 so as to extend in the widthwisedirection from both edges of the body section 10. Numeral 51 denotes thebase of each wing section 5 (the border between the body section 10 andeach wing section 5). A pressure-sensitive adhesive section 6 isprovided on the clothing side of each wing section 5. In FIG. 1, thewidthwise direction of the absorbent article 1 is the X direction, andthe lengthwise direction is the Y direction. The planar direction of theabsorbent article 1 is the XY direction.

The shape of the body section 10 is not particularly restricted so longas it is a shape suited to the female body and the shape of underwear,such as roughly rectangular, roughly elliptical or hourglass-shaped. Thedimensions of extension in the lengthwise direction of the outer shapeof the body section 10 are preferably 100 to 500 mm and more preferably150 to 350 mm. The dimensions of extension in the widthwise direction ofthe outer shape of the body section 10 are preferably 30 to 200 mm andmore preferably 40 to 180 mm.

The top sheet 2 transports body fluid such as urine and menstrual bloodthat has been excreted from a wearer into the absorbent body 4. At leasta portion of the top sheet 2 has a liquid-permeable property, and hasnumerous openings formed for permeation of body fluid.

The top sheet 2 is made of a resin film. The resin film used as the topsheet 2 is composed of a copolymer of an olefin and another monomer suchas an acrylic acid ester or vinyl acetate, or a polyolefin, polyester,polypropylene, polyethylene, polyethylene terephthalate, polyamide,cellulose acetate or the like. For high softness and reduced irritationto the skin, the resin film to be used as the top sheet 2 is mostpreferably a copolymer of an olefin and another monomer, or apolyolefin.

The basis weight of the top sheet 2 is preferably between 1 g/m² and 40g/m², and more preferably between 10 g/m² and 35 g/m². The thickness ofthe resin film forming the top sheet 2 is preferably between 0.01 mm and0.4 mm and more preferably between 0.1 mm and 0.35 mm. If the thicknessof the resin film forming the top sheet 2 is less than 0.01 mm, theconcealing property of the top sheet 2, described hereunder, may be toolow, while if the thickness of the resin film forming the top sheet 2exceeds 0.4 mm, the stiffness of the top sheet 2 may be increased andirritation by the top sheet 2 on the skin of the wearer may be toostrong. Since the top sheet 2 has protrusions as explained below, theapparent thickness of the top sheet 2 is greater than the thickness ofthe resin film forming the top sheet 2. The apparent thickness of thetop sheet 2 is preferably between 0.01 mm and 1 mm, and more preferablybetween 0.1 mm and 0.5 mm.

The top sheet 2 has a concealing property that prevents body fluidsabsorbed into the absorbent body 4 from being seen from the exterior.The concealing property of the top sheet 2 is produced by mixing afiller such as titanium oxide in a resin. When the filler is titaniumoxide, the titanium oxide content is preferably at least 1% and nogreater than 50%, and more preferably at least 3% and no greater than15%, with respect to the weight of the resin film. If the titanium oxidecontent is less than 1% with respect to the weight of the resin film,the concealing effect of the top sheet 2 for body fluids absorbed intothe absorbent body 4 may be too small. If the titanium oxide contentexceeds 50% of the weight of the resin film, it may become difficult toform a sheet from the titanium oxide-containing resin.

The first protrusions, second protrusions and bottom sections describedbelow are provided in the top sheet 2. The top sheet 2 in the region 12of the body section 10 in which the absorbent body 4 is provided is alsoprovided with openings, described below. Specifically, in the absorbentarticle 1 according to one embodiment of the invention, the region 12 ofthe body section 10 in which the absorbent body 4 is provided is theperforated region in which the openings described below have beenformed, and the regions 14 of the body section on the outer sides ofboth edges 41 in the widthwise direction of the absorbent body 4, andthe wing sections 5, are the non-perforated regions in which theopenings described below have not been formed. In the excretionhole-corresponding region 16 within the region 12 in which the absorbentbody 4 is provided, a blood modifying agent layer, described below, isformed on the surface of the top sheet 2. The excretionhole-corresponding region 16 is the region of the absorbent article 1,having a length in the lengthwise direction of preferably 50 to 200 mmand more preferably 70 to 150 mm, and a length in the widthwisedirection of preferably 10 to 80 mm and more preferably 20 to 50 mm,centered around the point corresponding to the excretion hole for bodyfluid of the wearer.

The top sheet 2 has a plurality of first protrusions 21 that extend inthe lengthwise direction and are aligned in the widthwise direction, aplurality of second protrusions 22 connecting the adjacent firstprotrusions 21, and bottom sections 23 which form the bases of the firstprotrusions 21 and second protrusions 22.

The first protrusions 21, second protrusions 22 and bottom sections 23provided in the top sheet 2 will now be explained in detail withreference to FIG. 3 and FIG. 4. FIG. 3 is a diagram for illustration ofthe first protrusions 21, second protrusions 22 and bottom sections 23formed in the regions 14 of the top sheet 2 of the body section 10 onthe outer sides of both edges 41 in the widthwise direction of theabsorbent body 4, and in the top sheet 2 of the wing sections 5 (seeFIG. 1).

As shown in FIG. 3, in the regions 14 on the outer sides of both edges41 in the widthwise direction of the absorbent body 4, and in the wingsections 5, the top sheet 2 comprises a plurality of first protrusions21 that extend in the lengthwise direction (Y direction) and are alignedin the widthwise direction (X direction). The cross-sectional shapes ofthe first protrusions 21 are, for example, approximate upside-downU-shapes (hereunder referred to as “approximate U-shapes”). “ApproximateU-shapes” include U-shapes, as well as shapes that become U-shapes bymodifications such as by rounding corners or curving straight lines. Forexample, “approximate U-shapes” include V-shaped and inverted M-shapedforms, as well as trapezoids.

As shown in FIG. 3, the top sheet 2 comprises, between adjacent firstprotrusions 21, a plurality of second protrusions 22 that extend in adirection diagonal to the first protrusions 21 which extend in thelengthwise direction (Y direction). For example, the angle formedbetween the first protrusions 21 and the second protrusions 22 ispreferably between 10° and 170°. The cross-sectional shapes of thesecond protrusions 22, as observed by cutting the second protrusions 22in the direction perpendicular to the direction in which the secondprotrusions 22 extend may be, for example, approximate invertedV-shapes. Incidentally, while the second protrusions 22 do not need tobe formed in the top sheet 2, since the first protrusions 21 are moreresistant to collapse if second protrusions 22 are formed, it ispreferred to provide the second protrusions 22 in the top sheet 2.

The first protrusions 21 and second protrusions 22 can reduce thecontact area between the skin of the wearer and the top sheet 2. Thiscan alleviate discomfort around the openings of underwear supporting theabsorbent article 1, when the underwear is worn. Also, the wing sections5 will tend to fold along the first protrusions 21 when the wingsections 5 are folded to anchor the absorbent article 1 to underwear.Consequently, the bending lines formed when the wing sections 5 havebeen folded allow folding of the wing sections 5 in a manner that is notsignificantly diagonal with respect to the edges of the openings of theunderwear.

The top sheet 2 does not comprise the openings described below in theregions 14 on the outer sides of both edges 41 in the widthwisedirection of the absorbent body 4 and in the wing sections 5. Thisprevents body fluid that has exuded from the edges 41 in the widthwisedirection of the absorbent body 4 (see FIG. 1) from exuding through theopenings onto the surface of the top sheet 2 in the regions 14 on theouter sides of both edges 41 in the widthwise direction of the absorbentbody 4, when the absorbent article 1 is subjected to pressure.

FIG. 4 is a diagram illustrating first protrusions 21, secondprotrusions 22 and bottom sections 23 formed in an excretionhole-corresponding region 16 of the top sheet 2 of an absorbent article1 according to an embodiment of the invention. As shown in FIG. 4, thetop sheet 2 at the excretion hole-corresponding region 16 comprisesfirst protrusions 21, second protrusions 22 and bottom sections 23,similar to the top sheet 2 at the regions 14 on the outer sides of bothedges 41 in the widthwise direction of the absorbent body 4 of the bodysection 10, and at the wing sections 5. However, the first protrusions21, second protrusions 22 and bottom sections 23 of the top sheet 2 inthe excretion hole-corresponding region 16 further comprise a bloodmodifying agent layer 24, described below, on the skin side surface. Thefirst protrusions 21 of the top sheet 2 in the excretionhole-corresponding region 16 also further comprise openings 25,described below. FIG. 5 is a photomicrograph of openings 25 formed inthe sides 26 of first protrusions.

The first protrusions 21 of the top sheet 2 in the excretionhole-corresponding region 16 have a plurality of openings 25 aligned inthe lengthwise direction (Y direction), on both sides 26. Body fluid ofa wearer, discharged into the top sheet 2 at the excretionhole-corresponding region 16, migrates through the openings 25 into theabsorbent body 4. Also, body fluid of the wearer discharged into the topsheet 2 rapidly collects toward the bottom sections 23 due to theapproximately U-shaped sections in the widthwise direction (X direction)formed by every two adjacent first protrusions 21 and the bottomsections 23. Since openings 25 are provided in the sides 26 of the firstprotrusions 21, body fluid flowing toward the bottom sections 23 passesthrough the openings 25 formed on the sides 26 of the first protrusions21 before reaching the bottom sections 23, and flows into the absorbentbody 4. Body fluid that has collected at the bottom sections 23 alsopasses through the openings 25 formed on the sides 26 of the firstprotrusions 21 and flows into the absorbent body 4. Body fluid of thewearer is therefore rapidly absorbed into the absorbent body 4 throughthe openings 25 provided on the sides 26 of the first protrusions 21.The amount of body fluid residing in the top sheet 2 can also be reducedby the openings 25 formed in the sides 26 of the first protrusions 21.

A blood modifying agent may also be coated on the surface of the skinside of the top sheet 2, at the excretion hole-corresponding region 16,to form a blood modifying agent layer 24 on the surface of theskin-contact side of the top sheet 2. The blood modifying agent layer 24can reduce residue of body fluids from the wearer, and especially highlyviscous body fluids (such as highly viscous menstrual blood), on thesurface of the top sheet 2. As long as the blood modifying agent layer24 is provided at least in the excretion hole-corresponding region 16 ofthe top sheet 2, a blood modifying agent layer 24 may be either providedor not provided in the regions other than the excretionhole-corresponding region 16. The blood modifying agent layer 24 will bedescribed in detail below.

The contact area between the skin of the wearer and the top sheet 2 isreduced by the first protrusions 21 provided on the top sheet 2 in theexcretion hole-corresponding region 16, and therefore the feel of thetop sheet 2 on the skin is satisfactory. Incidentally, the firstprotrusions alone may be formed on the top sheet 2 in the excretionhole-corresponding region 16, without forming any second protrusions.This will also reduce the contact area between the skin of the wearerand the top sheet 2, thus resulting in a satisfactory feel of the topsheet 2 on the skin. However, since the first protrusions are moreresistant to collapse if second protrusions are provided, it ispreferred to form both the first protrusions and second protrusions onthe top sheet 2 in the excretion hole-corresponding region 16.

First protrusions 21 with openings formed in the sides, secondprotrusions 22 and bottom sections 23 may also be formed in the topsheet 2 at regions within the region 12 of the body section 10 in whichthe absorbent body 4 is provided, other than the excretionhole-corresponding region 16, in a manner similar to the excretionhole-corresponding region 16. However, no blood modifying agent layer 24is formed on the surface of the top sheet 2 in those regions within theregion 12 of the body section 10 in which the absorbent body 4 isprovided, other than the excretion hole-corresponding region 16.

Body fluid of a wearer that has exuded from the excretionhole-corresponding region 16 due to a large discharge volume migratesthrough the openings 25 provided in the regions within the region 12 inwhich the absorbent body 4 is provided other than the excretionhole-corresponding region 16, and into the absorbent body 4. This canfurther inhibit body fluid discharged from the wearer from leaking outfrom the edges of the absorbent article 1.

A blood modifying agent layer 24 may be formed on the surface of the topsheet 2 in either some or all of the regions within the region 12 of thebody section 10 in which the absorbent body 4 is provided other than theexcretion hole-corresponding region 16. This can inhibit residue of bodyfluid of a wearer that has exuded from the excretion hole-correspondingregion 16, in the regions within the region 12 in which the absorbentbody 4 is provided other than the excretion hole-corresponding region16.

The contact area between the skin of the wearer and the top sheet 2 isreduced by the first protrusions 21 provided in the regions within theregion 12 of the body section 10 in which the absorbent body 4 isprovided, other than the excretion hole-corresponding region 16, andtherefore the feel of the top sheet 2 on the skin is satisfactory.Incidentally, the first protrusions alone may be formed on the top sheet2 in the regions within the region 12 of the body section 10 in whichthe absorbent body 4 is provided, other than the excretionhole-corresponding region 16, without forming any second protrusions.This will also reduce the contact area between the skin of the wearerand the top sheet 2, thus resulting in a satisfactory feel of the topsheet 2 on the skin. However, since the first protrusions are moreresistant to collapse if second protrusions are provided, it ispreferred to form both the first protrusions and second protrusions onthe top sheet 2 in the regions within the region 12 of the body section10 in which the absorbent body 4 is provided other than the excretionhole-corresponding region 16.

As long as openings 25 are provided in at least the excretionhole-corresponding region 16 of the top sheet 2, it is not necessary toprovide openings 25 in some or all of the regions within the region 12in which the absorbent body 4 is provided, other than the excretionhole-corresponding region 16. This is because in many cases openings 25do not need to be formed in the regions other than the excretionhole-corresponding region 16 if body fluid that has been discharged bythe wearer does not exude from the excretion hole-corresponding region16 on the surface of the top sheet 2. Also, openings 25 may be providedin the top sheet 2 of the body section 10, in a portion of the regions14 on the outer sides of both edges 41 in the widthwise direction of theabsorbent body 4. This will allow body fluid that has exuded from theregion 12 of the body section 10 in which the absorbent body 4 isprovided on the surface of the top sheet 2, to be absorbed into theabsorbent body 4 through the openings provided in the regions 14 on theouter sides of both edges 41 in the widthwise direction of the absorbentbody 4, thus further helping to prevent leakage of body fluid dischargedby the wearer from leaking out from the edges of the absorbent article1.

The back sheet 3 shown in FIG. 1 and FIG. 2 prevents body fluid that hasbeen absorbed into the absorbent body 4 from leaking to the outside. Amaterial that is impermeable to body fluids is used for the back sheet3. The material used for the back sheet 3 may be, for example, ahydrophobic nonwoven fabric, an impermeable plastic film or nonwovenfabric of polyethylene, polypropylene or the like, or a laminate sheetwith an impermeable plastic film. The material used for the back sheet 3may also be an SMS nonwoven fabric obtained by sandwiching a highlywater-resistant meltblown nonwoven fabric between high-strength spunbondnonwoven fabrics. By using a material which is not permeable to bodyfluids as the back sheet 3, it is possible to reduce mustiness duringwearing.

The absorbent body 4 absorbs and retains body fluids. The absorbent body4 preferably has high bulk, is resistant to deformation and has lowchemical irritation. For example, the absorbent body 4 may be acomposite absorbent body composed of fluffy pulp or an airlaid nonwovenfabric, and a super-absorbent polymer (SAP). The composite absorbentbody may also be covered with a liquid-permeable material such as atissue.

Instead of fluffy pulp in the composite absorbent body, there may beused, for example, artificial cellulose fiber such as chemical pulp,cellulose fiber, rayon or acetate. The basis weight of the absorbentfiber such as pulp in the composite absorbent body is and the mass ratioof the super-absorbent polymer in the composite absorbent body ispreferably at least 10% and no greater than 65%, with the absorbentfiber defined as 100%. The basis weight of the liquid-permeablematerial, such as a tissue, covering the composite mixture is preferablyat least 12 g/m² and no greater than 30 g/m².

An airlaid nonwoven fabric for the composite mixture may be, forexample, a nonwoven fabric comprising pulp and synthetic fiber heatsealed together, or a nonwoven fabric comprising pulp and syntheticfiber fixed with a binder.

The super-absorbent polymer of the composite absorbent body has athree-dimensional network structure with appropriate crosslinking of awater-soluble polymer. The absorbent polymer absorbs 30 to 60 times theamount of water relative to the volume of the absorbent polymer beforeabsorption of water. However, the absorbent polymer is essentiallywater-insoluble. The absorbent polymer does not exude absorbed watereven when a moderate degree of pressure is applied. The absorbentpolymer used is, for example, a starch-based, acrylic acid-based oramino acid-based particulate or filamentous polymer.

The shape and structure of the absorbent body 4 may be varied ifnecessary, but the total absorption by the absorbent body 4 must besuitable for the designed insertion volume and the desired use of theabsorbent article 1. The size and absorbing power of the absorbent body4 will also vary depending on the intended use.

The top sheet 2 and the absorbent body 4 are bonded to the back sheet 3using a hot-melt adhesive. This can inhibit peeling of the top sheet 2and absorbent body 4 from the back sheet 3.

The wing sections 5 are provided in the absorbent article 1 to stablyanchor the absorbent article 1 to underwear. After the wing sections 5have been folded on the outer side of the underwear, they are attachedto the crotch section of the underwear through the pressure-sensitiveadhesive section 6 to allow the absorbent article 1 to be stablyanchored to the underwear.

The pressure-sensitive adhesive section 6 anchors the absorbent article1 to the crotch section of the underwear. The pressure-sensitiveadhesive used to form the pressure-sensitive adhesive section 6 ispreferably, for example, one composed mainly of a styrene-based polymer,tackifier or plasticizer. Styrene-based polymers includestyrene-ethylene-butylene-styrene block copolymer, styrene-butylenepolymer, styrene-butylene-styrene block copolymer andstyrene-isobutylene-styrene copolymer, any of which may be used alone oras polymer blends of two or more. Styrene-ethylene-butylene-styreneblock copolymer is preferred among these from the viewpoint ofsatisfactory thermostability.

The tackifier and plasticizer mentioned above are preferably solids atordinary temperature, which include tackifiers such C5 petroleum resin,C9 petroleum resin, dicyclopentadiene-based petroleum resin, rosin-basedpetroleum resin, polyterpene resin, terpenephenol resin and the like,and plasticizers such as monomer plasticizers including tricresylphosphate, dibutyl phthalate and dioctyl phthalate, and polymerplasticizers including vinyl polymers and polyesters.

As shown in FIG. 1 and FIG. 2, the top sheet 2 and absorbent body 4 havecompressed grooves 7 from the top sheet 2 to the interior of theabsorbent body 4, formed by compression in the thickness direction byembossing. The compressed grooves 7 help prevent body fluid that hasbeen discharged into the excretion hole-corresponding region 16 of theabsorbent article 1 from diffusing in the widthwise direction (Xdirection). This can inhibit peeling of the top sheet 2 from theabsorbent body 4. The compressed grooves 7 surround the section of theabsorbent article 1 corresponding to the excretion hole of the wearer,and have roughly annular continuous shapes. The compressed grooves 7surrounding the section of the absorbent article 1 corresponding to theexcretion hole of the wearer may be partially interrupted. That is, thecompressed grooves 7 may have discontinuous annular shapes. Also,bonding of the top sheet 2 to the back sheet 3 by heat embossing formsseal sections 8 on both sides in the lengthwise direction and both sidesin the widthwise direction of the absorbent article 1. This can preventthe top sheet 2 from peeling from the back sheet 3.

The blood modifying agent layer 24 will now be described in detail. Theblood modifying agent layer 24 reduces the viscosity of the body fluid.The blood modifying agent layer 24 can also inhibit wetting of thesurface of the top sheet 2 with body fluid. As a result, the bloodmodifying agent layer 24 helps prevent body fluid of the wearer fromresiding on the surface of the top sheet 2 in the region in which theopenings 25 are formed.

The blood modifying agent of the blood modifying agent layer 24 has anIOB of about 0.00 to about 0.60, a melting point of no higher than about45° C., and a water solubility of about 0.00 to about 0.05 g in 100 g ofwater at 25° C.

The IOB (Inorganic Organic Balance) is an indicator of thehydrophilic-lipophilic balance, and as used herein, it is the valuecalculated by the following formula by Oda et al.:

IOB=inorganic value/organic value.

The inorganic value and the organic value are based on the organicparadigm described in “Organic compound predictions and organicparadigms” by Fujita A., Kagaku no Ryoiki (Journal of JapaneseChemistry), Vol. 11, No. 10 (1957) p. 719-725 which is incorporated byreference herein.

The organic values and inorganic values of major groups, according toFujita, are summarized in Table 1 below.

TABLE 1 Inorganic Organic Group value value —COOH 150 0 —OH 100 0—O—CO—O— 80 0 —CO— 65 0 —COOR 60 0 —O— 20 0 Triple bond 3 0 Double bond2 0 CH₂ 0 20 iso-branch 0 −10 tert-branch 0 −20 Light metal (salt) ≧5000 Heavy metal (salt), ≧400 0 amine, NH₃ salt

For example, in the case of an ester of tetradecanoic acid which has 14carbon atoms and dodecyl alcohol which has 12 carbon atoms, the organicvalue is 520 (CH₂, 20×26) and the inorganic value is 60 (—COOR, 60×1),and therefore IOB=0.12.

In the blood modifying agent, the IOB is about 0.00-0.60, preferablyabout 0.00-0.50, more preferably about 0.00-0.40 and even morepreferably about 0.00-0.30. This is because a lower IOB is associatedwith higher organicity and higher affinity with blood cells.

As used herein, the term “melting point” refers to the peak toptemperature for the endothermic peak during conversion from solid toliquid, upon measurement with a differential scanning calorimetryanalyzer at a temperature-elevating rate of 10° C./min. The meltingpoint may be measured using a Model DSC-60 DSC measuring apparatus byShimadzu Corp., for example.

If the blood modifying agent has a melting point of no higher than about45° C., it may be either liquid or solid at room temperature, or inother words, the melting point may be either about 25° C. or higher orbelow about 25° C., and for example, it may have a melting point ofabout −5° C. or about −20° C. The reason for a melting point of nohigher than about 45° C. for the blood modifying agent will be explainedbelow.

The blood modifying agent does not have a lower limit for its meltingpoint, but its vapor pressure is preferably low. The vapor pressure ofthe blood modifying agent is preferably between about 0 and about 200Pa, more preferably between about 0 and about 100 Pa, more preferablybetween about 0 and about 10 Pa, even more preferably between about 0and about 1 Pa and yet more preferably between about 0.0 and about 0.1Pa, at 25° C. (1 atmosphere). Considering that the absorbent article ofthe present disclosure is to be used in contact with the human body, thevapor pressure is preferably between about 0 and about 700 Pa, morepreferably between about 0 and about 100 Pa, more preferably betweenabout 0 and about 10 Pa, even more preferably between about 0 and about1 Pa and yet more preferably between about 0.0 and about 0.1 Pa, at 40°C. (1 atmosphere). If the vapor pressure of the blood modifying agent ishigh, gasification may occur during storage and the amount may bereduced, often creating problems such as odor during wear.

The melting point of the blood modifying agent may also differ dependingon the weather or duration of wear. For example, in regions with a meanatmospheric temperature of no higher than about 10° C., using a bloodmodifying agent with a melting point of no higher than about 10° C. mayallow the blood modifying agent to stably modify blood after excretionof menstrual blood, even if it has been cooled by the ambienttemperature.

Also, as the absorbent article may be used for a prolonged period oftime, the melting point of the blood modifying agent is preferably atthe high end of the range of no higher than about 45° C. This is becausethe blood modifying agent is not easily affected by sweat or frictionduring wearing, and will not easily migrate even during prolongedwearing.

The water solubility of 0.00-0.05 g may be measured by adding 0.05 g ofsample to 100 g of deionized water at 25° C., allowing it to stand for24 hours, and after 24 hours, gently stirring if necessary, and thenvisually evaluating whether or not the sample has dissolved.

As used herein, the term “solubility” in regard to water solubilityincludes cases where the sample completely dissolves in deionized waterto form a homogeneous mixture, and cases where the sample is completelyemulsified. As used herein, “completely” means that no mass of thesample remains in the deionized water.

When top sheet surfaces are coated with surfactants in order to alterthe surface tension of blood and promote the rapid absorption of blood,because surfactants generally have high water solubility, thesurfactant-coated top sheet is highly miscible with hydrophiliccomponents (such as blood plasma) in the blood and therefore, instead,they tend to cause residue of blood on the top sheet. The aforementionedblood modifying agent has low water solubility and therefore, it doesnot cause residue of blood on the top sheet and allows rapid migrationinto the absorbent body.

As used herein, a water solubility of water at 25° C. may be simplyreferred to as “water solubility”.

As used herein, “weight-average molecular weight” includes the conceptof a polydisperse compound (for example, a compound produced by stepwisepolymerization, an ester formed from a plurality of fatty acids and aplurality of aliphatic monohydric alcohols), and a simple compound (forexample, an ester formed from one fatty acid and one aliphaticmonohydric alcohol), and in a system comprising N_(i) molecules withmolecular weight M_(i) (i=1, or i=1, 2 . . . ), it refers to M_(w)determined by the following formula.

M _(w) =ΣN _(i) M _(i) ² /ΣN _(i) M _(i)

As used herein, the weight-average molecular weights are the valuesmeasured by gel permeation chromatography (GPC), based on polystyrene.

The GPC measuring conditions may be the following, for example.

Device: Lachrom Elite high-speed liquid chromatogram by HitachiHigh-Technologies Corp.

Columns: SHODEX KF-801, KF-803 and KF-804, by Showa Denko K.K.

Eluent: THF

Flow rate: 1.0 mL/min

Driving volume: 100 μL

Detection: RI (differential refractometer)

The weight-average molecular weights listed in the examples of thepresent specification were measured under the conditions describedbelow.

Preferably, the blood modifying agents is selected from the groupconsisting of the following items (i)-(iii), and any combinationthereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one ormore groups each selected from the group consisting of carbonyl group(—CO—) and oxy group (—O—) inserted between a C—C single bond of thehydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one ormore groups each selected from the group consisting of carbonyl group(—CO—) and oxy group (—O—) inserted between a C—C single bond of thehydrocarbon moiety, and (iii-3) one or more groups each selected fromthe group consisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting a hydrogen of the hydrocarbon moiety.

As used herein, “hydrocarbon” refers to a compound composed of carbonand hydrogen, and it may be a chain hydrocarbon, such as a paraffinichydrocarbon (containing no double bond or triple bond, also referred toas alkane), an olefin-based hydrocarbon (containing one double bond,also referred to as alkene), an acetylene-based hydrocarbon (containingone triple bond, also referred to as alkyne), or a hydrocarboncomprising two or more bonds each selected from the group consisting ofdouble bonds and triple bonds, and cyclic hydrocarbon, such as aromatichydrocarbons and alicyclic hydrocarbons.

Preferred as such hydrocarbons are chain hydrocarbons and alicyclichydrocarbons, with chain hydrocarbons being more preferred, paraffinichydrocarbons, olefin-based hydrocarbons and hydrocarbons with two ormore double bonds (containing no triple bond) being more preferred, andparaffinic hydrocarbons being even more preferred.

Chain hydrocarbons include linear hydrocarbons and branchedhydrocarbons.

When two or more oxy group (—O—) are inserted in the compounds of (ii)and (iii) above, the oxy group (—O—) are not adjacent to each other.Thus, compounds (ii) and (iii) do not include compounds with continuousoxy group (i.e., peroxides).

In the compounds of (iii), compounds in which at least one hydrogen onthe hydrocarbon moiety is substituted with a hydroxyl group (—OH) aremore preferred than compounds in which at least one hydrogen on thehydrocarbon moiety is substituted with a carboxyl group (—COOH). Asshown in Table 1, the carboxyl groups bond with metals and the like inmenstrual blood, drastically increasing the inorganic value from 150 to400 or greater, and therefore a blood modifying agent with carboxylgroups can increase the IOB value to more than about 0.6 during use,potentially lowering the affinity with blood cells.

More preferably, the blood modifying agent is a compound selected fromthe group consisting of the following items (i′)-(iii′), and anycombination thereof:

(i′) a hydrocarbon;

(ii′) a compound having at least (ii′-1) a hydrocarbon moiety, and(ii′-2) one or more bonds each selected from the group consisting ofcarbonyl bond (—CO—), at least one ester bond (—COO—), at least onecarbonate bond (—OCOO—), and/or at least one ether bond (—O—) insertedbetween a C—C single bond of the hydrocarbon moiety; and

(iii′) a compound having at least (iii′-1) a hydrocarbon moiety,(iii′-2) one or more bonds each selected from the group consisting ofcarbonyl bond (—CO—), at least one ester bond (—COO—), at least onecarbonate bond (—OCOO—), and/or at least one ether bond (—O—) insertedbetween a C—C single bond of a hydrocarbon, and (iii′-3) one or moregroups each selected from the group consisting of carboxyl group (—COOH)and hydroxyl group (—OH) substituting a hydrogen on the hydrocarbonmoiety.

When 2 or more same or different bonds are inserted in the compound of(ii′) or (iii′), i.e., when 2 or more bonds each selected from the groupconsisting of carbonyl bonds (—CO—), ester bonds (—COO—), carbonatebonds (—OCOO—) and ether bonds (—O—) are inserted, the bonds are notadjacent to each other, and at least one carbon atom lies between eachof the bonds.

The blood modifying agent is more preferably a compound with no morethan about 1.8 carbonyl bonds (—CO—), no more than 2 ester bonds(—COO—), no more than about 1.5 carbonate bonds (—OCOO—), no more thanabout 6 ether bonds (—O—), no more than about 0.8 carboxyl groups(—COOH) and/or no more than about 1.2 hydroxyl groups (—OH), per 10carbon atoms in the hydrocarbon moiety.

Even more preferably, the blood modifying agent may also be selectedfrom the group consisting of the following items (A)-(F), and anycombination thereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of ether bonds (—O—), carbonyl bonds (—CO—),ester bonds (—COO—) and carbonate bonds (—OCOO—) inserted in-between aC—C single bond of the chain hydrocarbon moiety;

(E) a polyoxy C₂₋C₆ alkylene glycol, or alkyl ester or alkyl etherthereof; and

(F) a chain hydrocarbon.

The blood modifying agent in accordance with (A) to (F) will now bedescribed in detail.

[(A) Ester of (A1) a Compound Having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting Hydrogens on the Chain Hydrocarbon Moiety,and (A2) a Compound Having a Chain Hydrocarbon Moiety and 1 CarboxylGroup Substituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (A) ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting a hydrogen on the chain hydrocarbon moiety(hereunder also referred to as “compound (A)”) includes esters of acompound with 4, 3 or 2 hydroxyl groups and a compound with 1 carboxylgroup, and it is not necessary for all of the hydroxyl groups to beesterified so long as the IOB, melting point and water solubility arewithin the aforementioned ranges.

Examples of (A1) a compound having a chain hydrocarbon moiety and 2-4hydroxyl groups substituting hydrogens on the chain hydrocarbon moiety(hereunder also referred to as “compound (A1)”) include chainhydrocarbon tetraols such as alkanetetraols, including pentaerythritol,chain hydrocarbon triols such as alkanetriols, including glycerins, andchain hydrocarbon diols such as alkanediols, including glycols. Examplesof (A2) a compound having a chain hydrocarbon moiety and 1 carboxylgroup substituting a hydrogen on the chain hydrocarbon moiety (hereunderalso referred to as “compound (A2)”) include compounds in which onehydrogen on the hydrocarbon is substituted with one carboxyl group(—COOH), such as fatty acids.

Examples for compound (A) include (a₁) an ester of a chain hydrocarbontetraol and at least one fatty acid, (a₂) an ester of a chainhydrocarbon triol and at least one fatty acid, and (a₃) an ester of achain hydrocarbon diol and at least one fatty acids.

[(a₁) Ester of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon tetraol and at least onefatty acid include tetraesters of pentaerythritol and fatty acids,represented by the following formula (1):

triesters of pentaerythritol and fatty acids, represented by thefollowing formula (2):

diesters of pentaerythritol and fatty acids, represented by thefollowing formula (3):

and monoesters of pentaerythritol and fatty acids, represented by thefollowing formula (4).

In the formulae, R¹-R⁴ each represent a chain hydrocarbon.

The fatty acids composing the esters of pentaerythritol and fatty acids(R¹COOH, R²COOH, R³COOH, and R⁴COOH) are not particularly restricted aslong as the pentaerythritol and fatty acid esters satisfy the conditionsfor the IOB, melting point and water solubility, and for example, theremay be mentioned saturated fatty acids, such as C₂-C₃₀ saturated fattyacids, including acetic acid (C₂) (C₂ representing the number ofcarbons, corresponding to the number of carbons of each of R¹C, R²C, R³Cor R⁴C, same hereunder), propanoic acid (C₃), butanoic acid (C₄) andisomers thereof such as 2-methylpropanoic acid (C₄), pentanoic acid (C₅)and isomers thereof such as 2-methylbutanoic acid (C₅) and2,2-dimethylpropanoic acid (C₅), hexanoic acid (C₆), heptanoic acid(C₇), octanoic acid (C₈) and isomers thereof, such as 2-ethylhexanoicacid (C₈), nonanoic acid (C₉), decanoic acid (C₁₀), dodecanoic acid(C₁₂), tetradecanoic acid (C₁₄), hexadecanoic acid (C₁₆), heptadecanoicacid (C₁₇), octadecanoic acid (C₁₈), eicosanoic acid (C₂₀), docosanoicacid (C₂₂), tetracosanoic acid (C₂₄), hexacosanoic acid (C₂₆),octacosanoic acid (C₂₈) and triacontanoic acid (C₃₀), as well as isomersof the foregoing (excluding those mentioned above).

The fatty acid may also be an unsaturated fatty acid. Examples ofunsaturated fatty acids include C₃-C₂₀ unsaturated fatty acids, such asmonounsaturated fatty acids including crotonic acid (C₄), myristoleicacid (C₁₄), palmitoleic acid (C₁₆), oleic acid (C₁₈), elaidic acid(C₁₈), vaccenic acid (C₁₈), gadoleic acid (C₂₀) and eicosenoic acid(C₂₀), di-unsaturated fatty acids including linolic acid (C₁₈) andeicosadienoic acid (C₂₀), tri-unsaturated fatty acids includinglinolenic acids, such as α-linolenic acid (C₁₈) and γ-linolenic acid(C₁₈), pinolenic acid (C₁₈), eleostearic acids, such as α-eleostearicacid (C₁₈) and β-eleostearic acid (C₁₈), Mead acid (C₂₀),dihomo-γ-linolenic acid (C₂₀) and eicosatrienoic acid (C₂₀),tetra-unsaturated fatty acids including stearidonic acid (C₂₀),arachidonic acid (C₂₀) and eicosatetraenoic acid (C₂₀),penta-unsaturated fatty acids including bosseopentaenoic acid (C₁₈) andeicosapentaenoic acid (C₂₀), and partial hydrogen adducts of theforegoing.

Considering the potential for degradation by oxidation and the like, theester of pentaerythritol and a fatty acid is preferably an ester ofpentaerythritol and a fatty acid, which is derived from a saturatedfatty acid, i.e., an ester of pentaerythritol and a saturated fattyacid.

Also, in order to lower the IOB and result in greater hydrophobicity,the ester of pentaerythritol and a fatty acid is preferably a diester,triester or tetraester, more preferably a triester or tetraester, andeven more preferably a tetraester.

In a tetraester of pentaerythritol and a fatty acid, the IOB is 0.60 ifthe total number of carbons of the fatty acid composing the tetraesterof the pentaerythritol and fatty acid, i.e., the total number of carbonsof the R¹C, R²C, R³C and R⁴C portions in formula (1), is 15. Thus, whenthe total number of carbons of the fatty acid composing the tetraesterof the pentaerythritol and fatty acid is approximately 15 or greater,the IOB satisfies the condition of being within about 0.00 to 0.60.

Examples of tetraesters of pentaerythritol and fatty acids includetetraesters of pentaerythritol with hexanoic acid (C₆), heptanoic acid(C₇), octanoic acid (C₈) such as 2-ethylhexanoic acid (C₈), nonanoicacid (C₉), decanoic acid (C₁₀) and/or dodecanoic acid (C₁₂).

In a triester of pentaerythritol and a fatty acid, the IOB is 0.58 ifthe total number of carbons of the fatty acid composing the triester ofthe pentaerythritol and fatty acid, i.e., the total number of carbons ofthe R¹C, R²C and R³C portions in formula (2), is 19. Thus, when thetotal number of carbons of the fatty acid composing the triester of thepentaerythritol and fatty acid is approximately 19 or greater, the IOBsatisfies the condition of being within about 0.00 to 0.60.

In a diester of pentaerythritol and a fatty acid, the IOB is 0.59 if thetotal number of carbons of the fatty acid composing the diester of thepentaerythritol and fatty acid, i.e., the total number of carbons of theR¹C or R²C portion in formula (3), is 22. Thus, when the total number ofcarbons of the fatty acid composing the diester of the pentaerythritoland fatty acid is approximately 22 or greater, the IOB satisfies thecondition of being within about 0.00 to 0.60.

In a monoester of pentaerythritol and a fatty acid, the IOB is 0.60 ifthe total number of carbons of the fatty acid composing the monoester ofthe pentaerythritol and fatty acid, i.e., the total number of carbons ofthe R¹C portion in formula (4), is 25. Thus, when the number of carbonsof the fatty acid composing the monoester of the pentaerythritol andfatty acid is approximately 25 or greater, the IOB satisfies thecondition of being within about 0.00 to 0.60.

The effects of double bonds, triple bonds, iso-branches andtert-branches are not considered in this calculation.

Commercial products which are esters of pentaerythritol and fatty acidsinclude UNISTAR H-408BRS and H-2408BRS-22 (mixed product) (both productsof NOF Corp.).

[(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon triol and at least one fattyacid include triesters of glycerin and fatty acids, represented byformula (5):

diesters of glycerin and fatty acids, represented by the followingformula (6):

and monoesters of glycerin and fatty acids, represented by the followingformula (7):

wherein R⁵-R⁷ each represent a chain hydrocarbon.

The fatty acid composing the ester of glycerin and a fatty acid (R⁵COOH,R⁶COOH and R⁷COOH) is not particularly restricted so long as the esterof glycerin and a fatty acid satisfies the conditions for the IOB,melting point and water solubility, and for example, there may bementioned that the fatty acids mentioned for the “(a₁) Ester of chainhydrocarbon tetraol and at least one fatty acids”, namely saturatedfatty acids and unsaturated fatty acids, and in consideration of thepotential for degradation by oxidation and the like, the ester ispreferably a glycerin and fatty acid ester, which is derived from asaturated fatty acid, i.e., an ester of glycerin and a saturated fattyacid.

Also, in order to lower the IOB and result in greater hydrophobicity,the ester of glycerin and a fatty acid is preferably a diester ortriester, and more preferably a triester.

A triester of glycerin and a fatty acid is also known as a triglyceride,and examples include triesters of glycerin and octanoic acid (C₈),triesters of glycerin and decanoic acid (C₁₀), triesters of glycerin anddodecanoic acid (C₁₂), triesters of glycerin and 2 or more differentfatty acids, and mixtures of the foregoing.

Examples of triesters of glycerin and 2 or more fatty acids includetriesters of glycerin with octanoic acid (C₈) and decanoic acid (C₁₀),triesters of glycerin with octanoic acid (C₈), decanoic acid (C₁₀) anddodecanoic acid (C₁₂), and triesters of glycerin with octanoic acid(C₈), decanoic acid (C₁₀), dodecanoic acid (C₁₂), tetradecanoic acid(C₁₄), hexadecanoic acid (C₁₆) and octadecanoic acid (C₁₈).

In order to obtain a melting point of no higher than about 45° C.,preferred triesters of glycerin and fatty acids are those with no morethan about 40 as the total number of carbons of the fatty acid composingthe triester of glycerin and the fatty acid, i.e., the total number ofcarbons of the R⁵C, R⁶C and R⁷C portions in formula (5).

In a triester of glycerin and a fatty acid, the IOB value is 0.60 whenthe total number of carbons of the fatty acid composing the triester ofglycerin and the fatty acid, i.e., the total number of carbons of theR⁵C, R⁶C and R⁷C portions in formula (5), is 12. Thus, when the totalnumber of carbons of the fatty acid comprising the triester of theglycerin and fatty acid is approximately 12 or greater, the IOBsatisfies the condition of being within about 0.00 to 0.60.

Triesters of glycerin and fatty acids, being aliphatic and thereforepotential constituent components of the human body are preferred fromthe viewpoint of safety.

Commercial products of triesters of glycerin and fatty acids includetri-coconut fatty acid glycerides, NA36, PANACET 800, PANACET 800B andPANACET 810S, and tri-C2L oil fatty acid glycerides and tri-CL oil fattyacid glycerides (all products of NOF Corp.).

A diester of glycerin and a fatty acid is also known as a diglyceride,and examples include diesters of glycerin and decanoic acid (C₁₀),diesters of glycerin and dodecanoic acid (C₁₂), diesters of glycerin andhexadecanoic acid (C₁₆), diesters of glycerin and 2 or more differentfatty acids, and mixtures of the foregoing.

In a diester of glycerin and a fatty acid, the IOB is 0.58 if the totalnumber of carbons of the fatty acid composing the diester of theglycerin and fatty acid, i.e., the total number of carbons of the R⁵Cand R⁶C portions in formula (6), is 16. Thus, when the total number ofcarbons of the fatty acid composing the diester of the glycerin andfatty acid is approximately 16 or greater, the IOB satisfies thecondition of being about 0.00 to 0.60.

Monoesters of glycerin and fatty acids are also known as monoglycerides,and examples include glycerin and icosanoic acid (C₂₀) monoester, andglycerin and docosanoic acid (C₂₂) monoester.

In a monoester of glycerin and a fatty acid, the IOB is 0.59 if thenumber of carbons of the fatty acid composing the monoester of theglycerin and fatty acid, i.e., the number of carbons of the R⁵C portionin formula (7), is 19. Thus, when the number of carbons of the fattyacid composing the monoester of the glycerin and fatty acid isapproximately 19 or greater, the IOB satisfies the condition of beingabout 0.00 to 0.60.

[(a₃) Ester of Chain Hydrocarbon Diol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon diol and at least one fattyacids include monoesters and diesters of fatty acids with C₂-C₆ chainhydrocarbon diols, such as C₂-C₆ glycols, including ethylene glycol,propylene glycol, butylene glycol, pentylene glycol and hexylene glycol.

Specifically, examples of an ester of a chain hydrocarbon diol and atleast one fatty acid include diesters of C₂-C₆ glycols and fatty acids,represented by the following formula (8):

R⁸COOC_(k)H_(2k)OCOR⁹  (8)

wherein k represents an integer of 2-6, and R⁸ and R⁹ each represent achain hydrocarbon, and monoesters of C₂-C₆ glycols and fatty acids,represented by the following formula (9):

R⁸COOC_(k)H_(2k)OH  (9)

wherein k represents an integer of 2-6, and R⁸ is a chain hydrocarbon.

The fatty acid to be esterified in an ester of a C₂-C₆ glycol and afatty acid (corresponding to R⁸COOH and R⁹COOH in formula (8) andformula (9)) is not particularly restricted so long as the ester of theC₂-C₆ glycol and fatty acid satisfies the conditions for the IOB,melting point and water solubility, and for example, there may bementioned that the fatty acids mentioned for the “(a₁) Ester of a chainhydrocarbon tetraol and at least one fatty acid”, namely saturated fattyacids and unsaturated fatty acids, and in consideration of the potentialfor degradation by oxidation and the like, it is preferably a saturatedfatty acid.

In a diester of butylene glycol (k=4) and a fatty acid represented byformula (8), IOB is 0.60 when the total number of carbons of the R⁸C andR⁹C portions is 6. Thus, when the total number of carbon atoms in adiester of butylene glycol (k=4) and a fatty acid represented by formula(8) is approximately 6 or greater, the IOB satisfies the condition ofbeing about 0.00-0.60. In a monoester of ethylene glycol (k=2) and afatty acid represented by formula (9), IOB is 0.57 when the number ofcarbons of the R⁸C portion is 12. Thus, when the total number of carbonatoms in the fatty acid composing a monoester of ethylene glycol (k=2)and a fatty acid represented by formula (9) is approximately 12 orgreater, the IOB satisfies the condition of being about 0.00-0.60.

Considering the potential for degradation by oxidation and the like, theester of the C₂-C₆ glycol and fatty acid is preferably a C₂-C₆ glycoland fatty acid ester, which is derived from a saturated fatty acid,i.e., an ester of a C₂-C₆ glycol and a saturated fatty acid.

Also, in order to lower the IOB and result in greater hydrophobicity,the ester of the C₂-C₆ glycol and fatty acid is preferably a glycol andfatty acid ester derived from a glycol with a greater number of carbons,such as an ester of a glycol and a fatty acid derived from butyleneglycol, pentylene glycol or hexylene glycol.

Also, in order to lower the IOB and obtain in greater hydrophobicity,the ester of a C₂-C₆ glycol and fatty acid is preferably a diester.

Examples of commercial products of esters of C₂-C₆ glycols and fattyacids include COMPOL BL and COMPOL BS (both products of NOF Corp.).

[(B) Ether of (B1) a Compound Having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting Hydrogens on the Chain Hydrocarbon Moietyand (B2) a Compound Having a Chain Hydrocarbon Moiety and 1 HydroxylGroup Substituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (B) ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety(hereunder also referred to as “compound (B)”) includes ethers of acompound with 4, 3 or 2 hydroxyl groups and a compound with 1 hydroxylgroup, and it is not necessary for all of the hydroxyl groups to beetherified as long as the IOB, melting point and water solubility arewithin the aforementioned ranges.

Examples of (B1) a compound having a chain hydrocarbon moiety and 2-4hydroxyl groups substituting hydrogens on the chain hydrocarbon moiety(hereunder also referred to as “compound (B1)”) include those mentionedfor “compound (A)”,)” as compound (A1), such as pentaerythritol,glycerin and glycol.

Examples of (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety(hereunder also referred to as “compound (B2)”) include compoundswherein 1 hydrogen on the hydrocarbon is substituted with 1 hydroxylgroup (—OH), such as aliphatic monohydric alcohols, including saturatedaliphatic monohydric alcohols and unsaturated aliphatic monohydricalcohols.

Examples of saturated aliphatic monohydric alcohols include C₁-C₂₀saturated aliphatic monohydric alcohols, such as methyl alcohol (C₁) (C₁representing the number of carbon atoms, same hereunder), ethyl alcohol(C₂), propyl alcohol (C₃) and isomers thereof, including isopropylalcohol (C₃), butyl alcohol (C₄) and isomers thereof, includingsec-butyl alcohol (C₄) and tert-butyl alcohol (C₄), pentyl alcohol (C₅),hexyl alcohol (C₆), heptyl alcohol (C₇), octyl alcohol (C₈) and isomersthereof, including 2-ethylhexyl alcohol (C₈), nonyl alcohol (C₉), decylalcohol (C₁₀), dodecyl alcohol (C₁₂), tetradecyl alcohol (C₁₄),hexadecyl alcohol (C₁₆), heptadecyl alcohol (C₁₇), octadecyl alcohol(C₁₈) and eicosyl alcohol (C₂₀), as well as their isomers other thanthose mentioned.

Unsaturated aliphatic monohydric alcohols include those wherein 1 C—Csingle bond of a saturated aliphatic monohydric alcohol mentioned aboveis replaced with a C═C double bond, such as oleyl alcohol, and forexample, these are commercially available by New Japan Chemical Co.,Ltd. as the RIKACOL Series and UNJECOL Series.

Examples for compound (B) include (b₁) an ether of a chain hydrocarbontetraol and at least one aliphatic monohydric alcohol, such asmonoethers, diethers, triethers and tetraethers, preferably diethers,triethers and tetraethers, more preferably triethers and tetraethers andeven more preferably tetraethers, (b₂) an ether of a chain hydrocarbontriol and at least one aliphatic monohydric alcohol, such as monoethers,diethers and triethers, preferably diethers and triethers and morepreferably triethers, and (b₃) an ether of a chain hydrocarbon diol andat least one aliphatic monohydric alcohols, such as monoethers anddiethers, and preferably diethers.

Examples of an ether of a chain hydrocarbon tetraol and at least onealiphatic monohydric alcohols include tetraethers, triethers, diethersand monoethers of pentaerythritol and aliphatic monohydric alcohols,represented by the following formulae (10)-(13):

wherein R¹⁰-R¹³ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon triol and at least onealiphatic monohydric alcohol include triethers, diethers and monoethersof glycerin and aliphatic monohydric alcohols, represented by thefollowing formulae (14)-(16):

wherein R¹⁴-R¹⁶ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon diol and at least onealiphatic monohydric alcohol include diethers of C₂-C₆ glycols andaliphatic monohydric alcohols, represented by the following formula(17):

R¹⁷OC_(n)H_(2n)OR¹⁸  (17)

wherein n is an integer of 2-6, and R¹⁷ and R¹⁸ are each a chainhydrocarbon,

and monoethers of C₂-C₆ glycols and aliphatic monohydric alcohols,represented by the following formula (18):

R¹⁷OC_(n)H_(2n)OH  (18)

wherein n is an integer of 2-6, and R¹⁷ is a chain hydrocarbon.

In the tetraether of pentaerythritol and an aliphatic monohydricalcohol, the IOB is 0.44 when the total number of carbon atoms of thealiphatic monohydric alcohol composing the tetraether of pentaerythritoland the aliphatic monohydric alcohol, i.e., the total number of carbonatoms of the R¹⁰, R¹¹, R¹² and R¹³ portions in formula (10), is 4. Thus,when the total number of carbon atoms of the aliphatic monohydricalcohol composing a tetraether of pentaerythritol and an aliphaticmonohydric alcohol is approximately 4 or greater, the IOB valuesatisfies the condition of being within about 0.00 to 0.60.

In the triether of pentaerythritol and an aliphatic monohydric alcohol,the IOB is 0.57 when the total number of carbon atoms of the aliphaticmonohydric alcohol composing the triether of pentaerythritol and thealiphatic monohydric alcohol, i.e., the total number of carbon atoms ofthe R¹⁰, R¹¹ and R¹² portions in formula (11), is 9. Thus, when thetotal number of carbon atoms of the aliphatic monohydric alcoholcomposing a triether of pentaerythritol and an aliphatic monohydricalcohol is approximately 9 or greater, the IOB value satisfies thecondition of being within about 0.00 to 0.60.

In the diether of pentaerythritol and an aliphatic monohydric alcohol,the IOB is 0.60 when the total number of carbon atoms of the aliphaticmonohydric alcohol composing the diether of pentaerythritol and thealiphatic monohydric alcohol, i.e., the total number of carbon atoms ofthe R¹⁰ and R¹¹ portions in formula (12), is 15. Thus, when the totalnumber of carbon atoms of the aliphatic monohydric alcohol composing adiether of pentaerythritol and an aliphatic monohydric alcohol isapproximately 15 or greater, the IOB value satisfies the condition ofbeing within about 0.00 to 0.60.

In the monoether of pentaerythritol and an aliphatic monohydric alcohol,the IOB is 0.59 when the number of carbon atoms of the aliphaticmonohydric alcohol composing the monoether of pentaerythritol and thealiphatic monohydric alcohol, i.e., the number of carbon atoms of theR¹⁰ portion in formula (13), is 22. Thus, when the number of carbonatoms of the aliphatic monohydric alcohol comprising a monoether ofpentaerythritol and an aliphatic monohydric alcohol is approximately 22or greater, the IOB value satisfies the condition of being within about0.00 to 0.60.

In the triether of glycerin and an aliphatic monohydric alcohol, the IOBis 0.50 when the total number of carbon atoms of the aliphaticmonohydric alcohol composing the triether of glycerin and the aliphaticmonohydric alcohol, i.e., the total number of carbon atoms of the R¹⁴,R¹⁵ and R¹⁶ portions in formula (14), is 3. Thus, when the total numberof carbon atoms of the aliphatic monohydric alcohol comprising atriether of glycerin and an aliphatic monohydric alcohol isapproximately 3 or greater, the IOB value satisfies the condition ofbeing within about 0.00 to 0.60.

In the diether of glycerin and an aliphatic monohydric alcohol, the IOBis 0.58 when the total number of carbon atoms of the aliphaticmonohydric alcohol composing the diether of glycerin and the aliphaticmonohydric alcohol, i.e., the total number of carbon atoms of the R¹⁴and R¹⁵ portions in formula (15), is 9. Thus, when the total number ofcarbon atoms of the aliphatic monohydric alcohol comprising a diether ofglycerin and an aliphatic monohydric alcohol is approximately 9 orgreater, the IOB value satisfies the condition of being within about0.00 to 0.60.

In the monoether of glycerin and an aliphatic monohydric alcohol, theIOB is 0.58 when the number of carbon atoms of the aliphatic monohydricalcohol composing the monoether of glycerin and the aliphatic monohydricalcohol, i.e., the number of carbon atoms of the R¹⁴ portion in formula(16), is 16. Thus, when the number of carbon atoms of the aliphaticmonohydric alcohol comprising a monoether of glycerin and an aliphaticmonohydric alcohol is approximately 16 or greater, the IOB valuesatisfies the condition of being within about 0.00 to 0.60.

In a diether of butylene glycol (n=4) and aliphatic monohydric alcoholrepresented by formula (17), the IOB is 0.33 when the total number ofcarbon atoms of the R¹⁷ and R¹⁸ portions is 2. Thus, when the number ofcarbon atoms of the aliphatic monohydric alcohol comprising a diether ofbutylene glycol (n=4) and an aliphatic monohydric alcohol represented byformula (17) is approximately 2 or greater, the IOB value satisfies thecondition of being within about 0.00 to 0.60. Also, in a monoether ofethylene glycol (n=2) and aliphatic monohydric alcohol represented byformula (18), the IOB is 0.60 when the number of carbon atoms of the R¹⁷portion is 8. Thus, when the number of carbon atoms of the aliphaticmonohydric alcohol in a monoether of ethylene glycol (n=2) and analiphatic monohydric alcohol represented by formula (18) isapproximately 8 or greater, the IOB value satisfies the condition ofbeing within about 0.00 to 0.60.

Compound (B) may be produced by dehydrating condensation of a compoundwith 2-4 hydroxyl groups (B1) and a compound with 1 hydroxyl group, suchas an aliphatic monohydric alcohol (B2), in the presence of an acidcatalyst.

[(C) Ester of (C1) a Carboxylic Acid, Hydroxy Acid, Alkoxy Acid orOxoacid Comprising a Chain Hydrocarbon Moiety and 2-4 Carboxyl GroupsSubstituting Hydrogens on the Chain Hydrocarbon Moiety and (C2) aCompound Having a Chain Hydrocarbon Moiety and 1 Hydroxyl GroupSubstituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (C) ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety (hereunder alsoreferred to as “compound (C)”) includes esters of a compound with 4, 3or 2 carboxyl groups and a compound with 1 hydroxyl group, and it is notnecessary for all of the carboxyl groups to be esterified so long as theIOB, melting point and water solubility are within the aforementionedranges.

Examples of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacidcomprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety (hereunder alsoreferred to as “compound (C1)”) include chain hydrocarbons hydrocarboncarboxylic acids with 2-4 carboxyl groups, such as chain hydrocarbondicarboxylic acids including alkanedicarboxylic acids such asethanedioic acid, propanedioic acid, butanedioic acid, pentanedioicacid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioicacid and decanedioic acid, chain hydrocarbon tricarboxylic acids,including alkanetricarboxylic acids such as propanetrioic acid,butanetrioic acid, pentanetrioic acid, hexanetrioic acid, heptanetrioicacid, octanetrioic acid, nonanetrioic acid and decanetrioic acid, andchain hydrocarbon tetracarboxylic acids, including alkanetetracarboxylicacids such as butanetetraoic acid, pentanetetraoic acid, hexanetetraoicacid, heptanetetraoic acid, octanetetraoic acid, nonanetetraoic acid anddecanetetraoic acid.

Compound (C1) includes chain hydrocarbon hydroxy acids with 2-4 carboxylgroups, including alkoxy acids with 2-4 carboxyl groups such as malicacid, tartaric acid, citric acid and isocitric acid, including chainhydrocarbon alkoxy acids with 2-4 carboxyl groups, such asO-acetylcitric acid, and chain hydrocarbon oxoacids with 2-4 carboxylgroups.

Compounds (C2) having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety include thosementioned for “compound (B)”, such as aliphatic monohydric alcohols.

Compound (C) may be (c₁) an ester, for example a monoester, diester,triester or tetraester, preferably a diester, triester or tetraester,more preferably a triester or tetraester and even more preferably atetraester, of a chain hydrocarbon tetracarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 4 carboxyl groups, and at least onealiphatic monohydric alcohol, (c₂) an ester, for example, a monoester,diester or triester, preferably a diester or triester and morepreferably a triester, of a chain hydrocarbon tricarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and atleast one aliphatic monohydric alcohol, or (c₃) an ester, for example, amonoester or diester, and preferably a diester, of a chain hydrocarbondicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxylgroups, and at least one aliphatic monohydric alcohol.

Examples for compound (C) include dioctyl adipate and tributyl0-acetylcitrate, of which commercially available products exist.

[(D) Compound Having a Chain Hydrocarbon Moiety and One Bond Selectedfrom the Group Consisting of an Ether Bond (—O—), Carbonyl Bond (—CO—),Ester Bond (—COO—) and Carbonate Bond (—OCOO—) Inserted in a ChainHydrocarbon Moiety and One Bond Selected from the Group Consisting of anEther Bond (—O—), Carbonyl Bond (—CO—), Ester Bond (—COO—) and CarbonateBond (—OCOO—) Inserted Between a C—C Single Bond of the ChainHydrocarbon Moiety]

The (D) compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of an ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—) inserted in-between a C—Csingle bond of the chain hydrocarbon moiety (hereunder also referred toas “compound (D)”) may be (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, or (d₄) adialkyl carbonate.

[(d₁) Ether of an Aliphatic Monohydric Alcohol and an AliphaticMonohydric Alcohol]

Ethers of aliphatic monohydric alcohols and aliphatic monohydricalcohols include compounds having the following formula (19):

R¹⁹OR²⁰  (19)

wherein R¹⁹ and R²⁰ each represent a chain hydrocarbon.

The aliphatic monohydric alcohol composing the ether (corresponding toR¹⁹OH and R²⁰OH in formula (19)) is not particularly restricted so longas the ether satisfies the conditions for the IOB, melting point andwater solubility, and for example, it may be one of the aliphaticmonohydric alcohols mentioned for “compound (B)”.

In an ether of an aliphatic monohydric alcohol and an aliphaticmonohydric alcohol, the IOB is 0.50 when the total number of carbonatoms of the aliphatic monohydric alcohols composing the ether, i.e.,the total number of carbons of the R¹⁰ and R²⁰ portions in formula (19),is 2, and therefore when the total number of carbons of the aliphaticmonohydric alcohols comprising the ether is about 2 or greater, thiscondition for the IOB is satisfied. However, when the total number ofcarbons of the aliphatic monohydric alcohols comprising the ether isabout 6, the water solubility is as high as about 2 g, which isproblematic from the viewpoint of vapor pressure as well. In order tosatisfy the condition of a water solubility of about 0.00-0.05 g, thetotal number of carbons of the aliphatic monohydric alcohols comprisingthe ether is preferably about 8 or greater.

[(d₂) Dialkyl Ketone]

The dialkyl ketone may be a compound of the following formula (20):

R²¹COR²²  (20)

wherein R²¹ and R²² are each an alkyl group.

In a dialkyl ketone, the IOB is 0.54 when the total number of carbonatoms of R²¹ and R²² is 5, and therefore this condition for the IOB issatisfied if the total number of carbons is about 5 or greater. However,when the total number of carbons of dialkyl ketone is about 5, the watersolubility is as high as about 2 g. Therefore, in order to satisfy thecondition of a water solubility of about 0.00-0.05 g, the total numberof carbons of dialkyl ketone is preferably about 8 or greater. Inconsideration of vapor pressure, the number of carbon atoms of dialkylketone is preferably about 10 or greater and more preferably about 12 orgreater.

If the total number of carbon atoms of alkyl ketone is about 8, such asin 5-nonanone, for example, the melting point is approximately −50° C.and the vapor pressure is about 230 Pa at 20° C.

The dialkyl ketone may be a commercially available product, or it may beobtained by a known method, such as by oxidation of a secondary alcoholwith chromic acid or the like.

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

Examples of esters of fatty acids and aliphatic monohydric alcoholsinclude compounds having the following formula (21):

R²³COOR²⁴  (21)

wherein R²³ and R²⁴ each represent a chain hydrocarbon.

Examples of fatty acids composing these esters (corresponding to R²³COOHin formula (21)) include the fatty acids mentioned for the “(a₁) anester of a chain hydrocarbon tetraol and at least one fatty acids”, andspecifically these include saturated fatty acids and unsaturated fattyacids, with saturated fatty acids being preferred in consideration ofthe potential for degradation by oxidation and the like. The aliphaticmonohydric alcohol composing the ester (corresponding to R²⁴OH informula (21)) may be one of the aliphatic monohydric alcohols mentionedfor “compound (B)”.

In an ester of such a fatty acid and aliphatic monohydric alcohol, theIOB is 0.60 when the total number of carbon atoms of the fatty acid andaliphatic monohydric alcohol, i.e., the total number of carbon atoms ofthe R²³C and R²⁴ portion in formula (21), is 5, and therefore thiscondition for the IOB is satisfied when the total number of carbon atomsof the R²³C and R²⁴ portion is about 5 or greater. However, with butylacetate in which the total number of carbon atoms is 6, the vaporpressure is high at greater than 2000 Pa. In consideration of vaporpressure, therefore, the total number of carbon atoms is preferablyabout 12 or greater. If the total number of carbon atoms is about 11 orgreater, it will be possible to satisfy the condition of a watersolubility of about 0.00-0.05 g.

Examples of esters of such fatty acids and aliphatic monohydric alcoholsinclude esters of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂) andesters of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂), andexamples of commercial products of esters of such fatty acids andaliphatic monohydric alcohols include ELECTOL WE20 and ELECTOL WE40(both products of NOF Corp.).

[(d₄) Dialkyl Carbonate]

The dialkyl carbonate may be a compound of the following formula (22):

R²⁵OC(═O)OR²⁶  (22)

wherein R²⁵ and R²⁶ are each an alkyl group.

In a dialkyl carbonate, the IOB is 0.57 when the total number of carbonatoms of R²⁵ and R²⁶ is 6, and therefore this condition for the IOB issatisfied if the total number of carbons of R²⁵ and R²⁶ is about 6 orgreater.

In consideration of water solubility, the total number of carbon atomsof R²⁵ and R²⁶ is preferably about 7 or greater and more preferablyabout 9 or greater.

The dialkyl carbonate may be a commercially available product, or it maybe synthesized by reaction between phosgene and an alcohol, reactionbetween formic chloride and an alcohol or alcoholate, or reactionbetween silver carbonate and an alkyl iodide.

[(E) Polyoxy C₂-C₆ Alkylene Glycol, or Alkyl Ester or Alkyl EtherThereof]

The (E) polyoxy C₂-C₆ alkylene glycol, or alkyl ester or alkyl etherthereof (hereunder also referred to as “compound (E)”) may be (e₁) apolyoxy C₂-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₂-C₆ alkyleneglycol and at least one fatty acid, (e₃) an ether of a polyoxy C₂-C₆alkylene glycol and at least one aliphatic monohydric alcohol, (e₄) anester of polyoxy C₂-C₆ alkylene glycol and a chain hydrocarbontetracarboxylic acid, chain hydrocarbon tricarboxylic acid or chainhydrocarbon dicarboxylic acid, or (e₅) an ether of polyoxy C₂-C₆alkylene glycol and chain hydrocarbon tetraol, chain hydrocarbon triolor chain hydrocarbon diol. These will now be explained.

[(e₁) Polyoxy C₂-C₆ Alkylene Glycol]

The polyoxy C₂-C₆ alkylene glycol is i) a homopolymer having onebackbone selected from the group consisting of polyoxy C₂-C₆ alkylenebackbones, i.e., oxyethylene backbone, oxypropylene backbone,oxybutylene backbone, oxypentylene backbone and oxyhexylene backbone,and having hydroxy groups at both ends, ii) a block copolymer having abackbone of 2 or more selected from among the aforementioned group andhaving hydroxy groups at both ends, or iii) a random copolymer having abackbone of two or more selected from among the aforementioned group andhaving hydroxy groups at both ends.

The polyoxy C₂-C₆ alkylene backbone is preferably an oxypropylenebackbone, oxybutylene backbone, oxypentylene backbone or oxyhexylenebackbone and more preferably an oxybutylene backbone, oxypentylenebackbone or oxyhexylene backbone, from the viewpoint of lowering the IOBof the polyoxy C₂-C₆ alkylene glycol.

When polyoxy C₂-C₆ alkylene glycol is a homopolymer, the poly C₃₋₆alkylene glycol is represented by the following formula (23):

HO—(C_(m)H_(2m)O)_(n)—H  (23)

wherein m is an integer of 3-6.

The present inventors have confirmed that in polyethylene glycol(corresponding to formula (23) where m=2), when n≧45 (the molecularweight exceeds about 2,000), the condition for IOB of about 0.00 toabout 0.60 is satisfied, but the condition for the water solubility isnot satisfied even when the molecular weight exceeds 4,000. Therefore,ethylene glycol homopolymer is not included in the (e₁) polyoxy C₂-C₆alkylene glycol, and ethylene glycol should be included in the (e₁)polyoxy C₂-C₆ alkylene glycol only as a copolymer or random polymer withanother glycol.

Thus, homopolymers of formula (23) may include propylene glycol,butylene glycol, pentylene glycol or hexylene glycol homopolymer.

For this reason, m in formula (23) is about 3 to 6 and preferably about4 to 6, and n is 2 or greater.

The value of n in formula (23) is a value such that the polyoxy C₂-C₆alkylene glycol has an IOB of about 0.00-0.60, a melting point of nohigher than about 45° C. and a water solubility of no greater than about0.05 g in 100 g of water at 25° C.

For example, when formula (23) is polypropylene glycol (m=3), the IOB is0.58 when n=12. Thus, when formula (23) is polypropylene glycol (m=3),the condition for the IOB is satisfied when n is equal to or greaterthan about 12.

Also, when formula (23) is polybutylene glycol (m=4), the IOB is 0.57when n=7. Thus, when formula (23) is polybutylene glycol (m=4), thecondition for the IOB is satisfied when n is equal to or greater thanabout 7.

From the viewpoint of IOB, melting point and water solubility, theweight-average molecular weight of the polyoxy C₂-C₆ alkylene glycol ispreferably between about 200 and about 10,000, more preferably betweenabout 250 and about 8,000, and even more preferably in the range ofabout 250 to about 5,000.

Also from the viewpoint of IOB, melting point and water solubility, theweight-average molecular weight of a poly C₃ alkylene glycol, i.e.,polypropylene glycol, is preferably between about 1,000 and about10,000, more preferably between about 3,000 and about 8,000, and evenmore preferably between about 4,000 and about 5,000. This is because ifthe weight-average molecular weight is less than about 1,000, thecondition for the water solubility will not be satisfied, and a largerweight-average molecular weight will particularly tend to increase themigration rate into the absorbent body and the whiteness of the topsheet.

Examples of commercial products of polyoxy C₂-C₆ alkylene glycolsinclude UNIOL™ D-1000, D1200, D-2000, D-3000, D-4000, PB-500, PB-700,PB-1000 and PB-2000 (both products of NOF Corp.).

[(e₂) Ester of Polyoxy C₂-C₆ Alkylene Glycol and at Least One FattyAcid]

Esters of such polyoxy C₂-C₆ alkylene glycols and at least one fattyacid include the polyoxy C₂-C₆ alkylene glycols mentioned for “(e₁)Polyoxy C₂-C₆ alkylene glycol” in which one or both OH ends have beenesterified with fatty acids, i.e., monoesters and diesters.

Examples of fatty acids to be esterified in the ester of a polyoxy C₂-C₆alkylene glycol and at least one fatty acid include the fatty acidsmentioned for the “(a₁) Esters of chain hydrocarbon tetraols and atleast one fatty acid”, and specifically these include saturated fattyacids and unsaturated fatty acids, with saturated fatty acids beingpreferred in consideration of the potential for degradation by oxidationand the like. An example of a commercially available ester of a polyoxyC₂-C₆ alkylene glycol a fatty acid is WILLBRITE cp9 (product of NOFCorp.).

[(e₃) Ether of Polyoxy C₂-C₆ Alkylene Glycol and at Least One AliphaticMonohydric Alcohol]

Ethers of such polyoxy C₂-C₆ alkylene glycols and at least one aliphaticmonohydric alcohol include the polyoxy C₂-C₆ alkylene glycols mentionedfor “(e₁) polyoxy C₂-C₆ alkylene glycol” wherein one or both OH endshave been etherified by an aliphatic monohydric alcohol, i.e.,monoethers and diethers.

In an ether of a polyoxy C₂-C₆ alkylene glycol and at least onealiphatic monohydric alcohol, the aliphatic monohydric alcohol to beetherified may be an aliphatic monohydric alcohol among those mentionedfor “compound (B)”.

[(e₄) Ester of Polyoxy C₂-C₆ Alkylene Glycol and Chain HydrocarbonTetracarboxylic Acid, Chain Hydrocarbon Tricarboxylic Acid or ChainHydrocarbon Dicarboxylic Acid]

The polyoxy C₂-C₆ alkylene glycol to be esterified for theaforementioned ester of a polyoxy C₂-C₆ alkylene glycol and a chainhydrocarbon tetracarboxylic acid, chain hydrocarbon tricarboxylic acidor chain hydrocarbon dicarboxylic acid may be any of the polyoxy C₂-C₆alkylene glycols mentioned above under “(e₁) Polyoxy C₂-C₆ alkyleneglycol”. Also, the chain hydrocarbon tetracarboxylic acid, chainhydrocarbon tricarboxylic acid or chain hydrocarbon dicarboxylic acid tobe esterified may be any of those mentioned above for “compound (C)”.

The ester of a polyoxy C₂-C₆ alkylene glycol and a chain hydrocarbontetracarboxylic acid, chain hydrocarbon tricarboxylic acid or chainhydrocarbon dicarboxylic acid may be a commercially available product,or it may be produced by polycondensation of a polyoxy C₂-C₆ alkyleneglycol with a chain hydrocarbon tetracarboxylic acid, chain hydrocarbontricarboxylic acid or chain hydrocarbon dicarboxylic acid under knownconditions.

[(e₅) Ether of Polyoxy C₂-C₆ Alkylene Glycol and Chain HydrocarbonTetraol, Chain Hydrocarbon Triol or Chain Hydrocarbon Diol]

The polyoxy C₂-C₆ alkylene glycol to be etherified for theaforementioned ether of a polyoxy C₂-C₆ alkylene glycol and a chainhydrocarbon tetraol, chain hydrocarbon triol or chain hydrocarbon diolmay be any of the polyoxy C₂-C₆ alkylene glycols mentioned above under“(e₁) Polyoxy C₂-C₆ alkylene glycol”. Also, the chain hydrocarbontetraol, chain hydrocarbon triol or chain hydrocarbon diol to beetherified may be, for example, pentaerythritol, glycerin or glycol,mentioned above for “compound (A)”.

Examples of commercially available ethers of polyoxy C₂-C₆ alkyleneglycols and chain hydrocarbon tetraols, chain hydrocarbon triols andchain hydrocarbon diols include UNILUBE™ 5TP-300 KB and UNIOL™ TG-3000and TG-4000 (products of NOF Corp.).

UNILUBE™ 5TP-300 KB is a compound obtained by polycondensation of 65 molof propylene glycol and 5 mol of ethylene glycol with 1 mol ofpentaerythritol, and it has an IOB of 0.39, a melting point of below 45°C., and a water solubility of less than 0.05 g.

UNIOL™ TG-3000 is a compound obtained by polycondensation of 50 mol ofpropylene glycol with 1 mol of glycerin, and it has an IOB of 0.42, amelting point of below 45° C., a water solubility of less than 0.05 g,and a weight-average molecular weight of about 3,000.

UNIOL™ TG-4000 is a compound obtained by polycondensation of 70 mol ofpropylene glycol with 1 mol of glycerin, and it has an IOB of 0.40, amelting point of below 45° C., a water solubility of less than 0.05 g,and a weight-average molecular weight of about 4,000.

The ether of a poly C₂-C₆ alkylene glycol and a chain hydrocarbontetraol, chain hydrocarbon triol or chain hydrocarbon diol may also beproduced by polycondensation of a polyoxy C₂-C₆ alkylene glycol with achain hydrocarbon tetraol, chain hydrocarbon triol or chain hydrocarbondiol under known conditions.

[(F) Chain Hydrocarbon]

The chain hydrocarbon has an inorganic value of 0 and thus an IOB of0.00, while the water solubility is also approximately 0 g, andtherefore if the melting point is no higher than about 45° C., it may beincluded among the aforementioned blood modifying agents. Examples ofsuch chain hydrocarbons include (f₁) chain alkanes, such as linearalkanes and branched alkanes, and linear alkanes generally include thosewith no more than 22 carbons, in consideration of a melting point of nohigher than about 45° C. In consideration of vapor pressure, theygenerally include those with 13 or more carbons. Branched alkanesgenerally include those with 22 or more carbons, since their meltingpoints are often lower than linear alkanes, given the same number ofcarbon atoms.

Examples of commercially available hydrocarbon products include PARLEAM6 (NOF Corp.).

The blood modifying agent has been found to exhibit at least action oflowering blood viscosity and surface tension, which will be consideredin detail in the examples. Menstrual blood to be absorbed by theabsorbent article, unlike ordinary blood, contains proteins of theendometrial wall, for example, which act to bind together blood cells sothat the blood cells form a rouleau state. Menstrual blood which is tobe absorbed by the absorbent article therefore tends to have highviscosity, and when the top sheet is a nonwoven fabric or woven fabric,the menstrual blood becomes clogged between the fibers creating aresidual sticky feel for the wearer, while the menstrual blood alsodiffuses on the surface of the top sheet and tends to leak.

In addition, the blood modifying agent which has an IOB of about 0.00 to0.60 has high organicity and readily infiltrates between blood cells,and it therefore stabilizes the blood cells and can prevent formation ofa rouleau structure by the blood cells. It is believed that, since themodifier stabilizes blood cells and helps to prevent formation of arouleau structure by the blood cells, it facilitates absorption ofmenstrual blood by the absorbent body. For example, with an absorbentarticle comprising an acrylic super-absorbent polymer, or SAP,absorption of menstrual blood is known to lead to covering of the SAPsurface by rouleau-formed blood cells and inhibition of the absorptionperformance of the SAP, but presumably stabilization of the blood cellsallows the absorption performance of the SAP to be exhibited moreeasily. In addition, the blood modifying agent which has high affinitywith erythrocytes protects the erythrocyte membranes, and therefore mayminimize destruction of the erythrocytes.

A method for producing the absorbent article 1 according to anembodiment of the invention will now be explained with reference to FIG.6. FIG. 6 is an illustration of an absorbent article productionapparatus 100 to be used in a method for producing an absorbent article1 according to an embodiment of the invention. The method for producingthe absorbent article 1 comprises a step of forming an absorbent body, astep of preparing a sheet for a top sheet, a step of forming compressedgrooves in a layered body, a step of preparing a sheet for a back sheet,a step of cutting continuous sections in the absorbent article, and astep of coating the absorbent article with a blood modifying agent. Thesheet for a top sheet, which is to be used in the step of preparing asheet for a top sheet, is produced by a method for producing a sheet fora top sheet comprising a step of preparing a resin film sheet, a step offorming recesses in the resin film sheet and a step of gear stretchingthe resin film sheet.

In the step of forming the absorbent body, the absorbent body 128 isformed on a belt 110. Ground pulp 122 is supplied from a ground pulpsupply apparatus (not shown), to a pattern drum 120. Recesses 124 areformed around the outer periphery of the pattern drum 120, as a moldinto which the ground pulp is to be filled. The interior of the patterndrum 120 is aspirated 126, and the ground pulp 122 supplied to thepattern drum 120 is drawn into the recesses 124 and compressed. Thecompressed pulp 122 in the recesses 124 is molded into an absorbent body128. The absorbent body 128 is placed on a belt.

In the step of preparing the sheet for a top sheet, the sheet for a topsheet 216, produced by the method for producing a sheet for a top sheetdescribed below, is placed on the absorbent body 128 and the sheet for atop sheet 216 is bonded to the absorbent body 128.

In the step of forming compressed grooves in the layered body, anembossing apparatus 130 is used to form compressed grooves in the sheetfor a top sheet 216 and the layered body 262 of the absorbent body 128.The layered body 262 passes between the upper roll 131 and lower roll132 of the embossing apparatus 130. Heights (not shown) with shapescorresponding to the compressed grooves 7 of the absorbent article 1shown in FIG. 1 are provided on the outer peripheral surface of theupper roll 131. The lower roll 132 is a plain roll having a smooth outerperipheral surface. By passing the layered body 262 between the upperroll 131 and lower roll 132 of the embossing apparatus 130, the sectionscorresponding to the compressed grooves 7 of the absorbent article 1shown in FIG. 1 become compressed in the thickness direction of thelayered body 262, forming compressed grooves in the layered body 262.

In the step of preparing the sheet for the back sheet, the sheet 142 fora back sheet supplied from a back sheet roll 140 is coated with anadhesive using a coating applicator (not shown), and it is then bondedwith the surface of the layered body 134 on which the compressed grooveshave been formed, on the side opposite the side for the sheet for a topsheet, to form continuous sections 144 in the absorbent article.

In the step of cutting the continuous sections of the absorbent article,a cutter 150 is used for cutting of the continuous sections 144 of theabsorbent article into the shape of the absorbent article, producing anabsorbent article.

In the step of coating the absorbent article with a blood modifyingagent, a modifying agent-coating spray 160 is used to coat the bloodmodifying agent 161 onto the center region of the absorbent article,forming a blood modifying agent layer on the surface of the excretionhole-corresponding region of the top sheet.

Here, the blood modifying agent was coated after the step of cutting thecontinuous sections of the absorbent article, but the blood modifyingagent may instead be coated in the step of producing the sheet for a topsheet described hereunder. In order to prevent the coated bloodmodifying agent from falling from the absorbent article duringproduction of the absorbent article, it is preferred to coat the bloodmodifying agent onto the absorbent article at a stage downstream fromthe absorbent article production step, such as immediately beforepackaging the absorbent article.

The method for producing the absorbent article 1 may further comprise astep of forming a pressure-sensitive adhesive section on the continuoussections 144 of the absorbent article, and a step of forming a sealsection on the continuous sections 144 of the absorbent article.

A method for producing a sheet for a top sheet will now be described.

In the step of preparing the resin film sheet, as shown in FIG. 6, theresin film sheet 212 supplied from a resin film sheet roll 210 issupplied to a recess-forming roll 220.

In the step of forming recesses in the resin film sheet, the resin filmsheet 212 is passed through recess-forming rolls 220 to produce a resinfilm sheet 214 having recesses 2141 formed therein (see FIG. 8). Therecess-forming roll 220 comprises a roulette roll 221 and a preheatedroll 222 with a smooth surface.

FIGS. 7( a) and (b) show an example of the roulette roll 221. FIG. 7( a)shows the entire roulette roll 221, and FIG. 7( b) is a magnified viewof section 223 having concavoconvexities on the outer peripheral surfaceof the roulette roll 221. FIG. 7( c) shows an example of the preheatedroll 222 which has a smooth surface. Lattice-like heights 224 are formedon the surface 223 of the roulette roll 221. As a result, rhomboidrecesses 225 are formed in the surface of the roulette roll 221. Theshapes of the recesses 225 of the roulette roll 221 are not limited tobeing rhomboid, and may instead be square, rectangular,parallelogram-shaped, trapezoid, triangular, hexagonal, or the like.

The center line spacing between the heights 224 arranged parallel on thelattice-like heights 224, i.e. the pitch of the lattice-like heights224, is preferably at least 0.2 mm and no greater than 10 mm and morepreferably at least 0.4 mm and no greater than 2 mm. If the pitch of thelattice-like heights 224 is less than 0.2 mm or greater than 10 mm,recesses may not form in the resin film. The widths of the lattice-likeheights 224 are preferably at least 0.01 mm and no greater than 1 mm,and more preferably at least 0.03 mm and no greater than 0.1. Thelengths of the sides of the rhomboid recesses 225 are preferably atleast 0.1 mm and no greater than 5 mm, and more preferably at least 0.2mm and no greater than 1 mm. If the widths of the lattice-like heights224 are less than 0.01 mm or greater than 1 mm, or if the lengths of thesides of the rhomboid recesses 225 are less than 0.1 mm or greater than5 mm, recesses may not form in the resin film.

The preheated roll 222 with a smooth surface is kept at a temperaturebetween 70° C. and 100° C., and it heats the supplied resin film sheet212. This softens the resin film sheet 212 and facilitates formation.

When the resin film sheet 212 passes between the roulette roll 221 andthe roll 222 with a smooth surface, the resin film sheet 212 receivesstrong pressure in the thickness direction at the sections in contactwith the lattice-like heights 224. This causes thin recesses 2141 toform in the resin film sheet 214, as shown in FIG. 8. The recesses 2141formed in the resin film sheet 212 are actually smaller than shown inFIG. 8, and the number of recesses 2141 per unit area is much greaterthan shown in FIG. 8. The recesses 2141 are formed only in the region2143 of the resin film sheet 214 corresponding to the region 12 of theabsorbent article 1 in which the absorbent body 4 is provided (see FIG.1). The region of the resin film sheet 214 corresponding to theabsorbent article 1 is the region indicated by the dotted line denotedas 2142.

In the step of gear stretching the resin film sheet, the firstprotrusions, second protrusions and bottom sections of the top sheet 2are formed in the resin film sheet 214 by passing the recess-formedresin film sheet 214 through the stretching gear roll 230 shown in FIG.6. Numeral 216 denotes the resin film sheet in which the firstprotrusions, second protrusions and bottom sections have been formed.

The stretching gear roll 230 comprises an upper roll 231 and a lowerroll 232. FIG. 9( a) is a diagram illustrating the upper roll 231 of thestretching gear roll 230, FIG. 9( b) is a diagram illustrating the gearteeth 233 situated on the peripheral surface of the upper roll 231, andFIG. 9( c) is a cross-sectional view of FIG. 9( b) along line B-B. Thegear teeth 233 extend in a discontinuous manner in the circumferentialdirection of the upper roll 231. That is, the gear teeth 233 extendingin the circumferential direction of the upper roll 231 are interruptedat multiple locations along them. The locations 234 where the gear teeth233 are interrupted result in formation of second protrusions in theresin film sheet 214.

The widths of the gear teeth 233 are between 0.3 mm and 0.5 mm, forexample, and the distance between the centers of the adjacent gear teeth233 are between 1.0 mm and 1.2 mm, for example.

FIG. 10( a) is a diagram illustrating the lower roll 232 of thestretching gear roll 230, FIG. 10( b) is a diagram illustrating the gearteeth 235 situated on the peripheral surface of the lower roll 232, andFIG. 10( c) is a cross-sectional view of FIG. 10( b) along line C-C. Thegear teeth 235 extend in the circumferential direction of the lower roll232. The lower roll 232, unlike the upper roll 231, is not interruptedat multiple locations along it. The widths of the gear teeth 235 may beequal to the widths of the gear teeth 233 of the upper roll 231, forexample, and the distance between the centers of adjacent gear teeth 235may be equal to the distance between the centers of the gear teeth 233of the upper roll 231, for example.

The length of the upper roll 231 in the radial direction at the sectionwhere the gear teeth 233 of the upper roll 231 engage with the gearteeth 235 of the lower roll 232, i.e. the mesh depth, is 1.25 mm, forexample. The gaps between the gear teeth 233 of the upper roll 231 andthe gear teeth 235 of the lower roll 232, when the gear teeth 233 of theupper roll 231 and the gear teeth 235 of the lower roll 232 have beenmeshed, are between 0.25 mm and 0.45 mm, for example.

As shown in FIG. 6, when the resin film sheet 214 passes through thestretching gear roll 230, the resin film 214 is bent into a roughlyundulating form, forming the first protrusions 21 and second protrusions22 of the top sheet 2 in the resin film 214. Openings 25 of the topsheet 2 (see FIG. 4) are also formed in the region 2143 of the resinfilm sheet 214 in which the recesses 2141 have been formed (see FIG.10).

The principle by which openings are formed in the resin film sheet 214after the resin film sheet 214 has passed through the stretching gearroll 230 will now be explained with reference to FIG. 11. Theexplanation of this principle is not intended to limit the scope of theinvention.

The resin film sheet 214 is stretched to a large degree at the sections236 where the gear teeth 233 of the upper roll 231 and the gear teeth235 of the lower roll 232 are meshed. Since the resin film sheet 214 isthinner at the sections in which the recesses 2141 (see FIG. 8) havebeen formed in the recess-forming step, and they are also the sectionsthat have been damaged by the lattice-like heights 224 of the rouletteroll 221, their strength is weak and the recesses 2141 of the resin filmsheet 214 tear when subjected to stretching. As a result, the recesses2141 of the resin film sheet 214 tear at the sections 236 of the resinfilm sheet 214 that have been stretched, such that the torn sections ofthe resin film sheet 214 widen, forming openings at the sections wherethe resin film sheet 214 has torn.

The resin film sheet 214 is not significantly stretched at the sections237, 238 where the gear teeth 233 of the upper roll 231 and the gearteeth 235 of the lower roll 232 are not meshed. Consequently, even whenthe resin film sheet 241 passes through the stretching gear roll 230,the recesses 2141 formed in the recess-forming step are not torn and donot become openings at the sections 237, 238 of the resin film sheet 214where the gear teeth 233 of the upper roll 231 and the gear teeth 235 ofthe lower roll 232 are not meshed.

In the regions of the resin film sheet 214 where no recesses 2141 havebeen formed, the resin film sheet 214 is not torn even when the resinfilm sheet 214 is stretched to a high degree, at the section 236 wherethe gear teeth 233 of the upper roll 231 and the gear teeth 235 of thelower roll 232 are meshed. Consequently, openings are not formed in theregions of the resin film sheet 214 corresponding to the regions 14 ofthe body section 10 on the outer sides of both edges 41 in the widthwisedirection of the absorbent body 4, and to the wing sections 5.

The absorbent article 1 according to an embodiment of the invention mayalso be modified as follows.

(1) The absorbent article may lack wing sections. That is, the absorbentarticle may consist of only the body section. In this case,pressure-sensitive adhesive sections are provided on the clothing sidesurface of the body section, allowing the absorbent article to beanchored to underwear even without wing sections.

(2) The top sheet of the invention is not limited to the top sheet 2 ofthe absorbent article 1 according to the embodiment of the invention, solong as the top sheet has perforated regions in which openings areformed and non-perforated regions in which openings are not formed, theperforated regions are provided at least in the excretionhole-corresponding region corresponding to the body fluid excretion holeof the wearer, and a blood modifying agent layer is formed at least onthe surface of the excretion hole-corresponding region. FIG. 12( a) is aschematic diagram showing a top sheet for the excretionhole-corresponding region as a modified example of an absorbent articleaccording to an embodiment of the invention, and FIG. 12( b) is aschematic diagram showing a top sheet for the regions on the outer sidesof both edges of the body section in the widthwise direction of theabsorbent body, and the wing sections, as a modified example of anabsorbent article according to an embodiment of the invention. Forexample, the openings 25A and blood modifying agent layer 24A may beprovided without providing first protrusions 21, second protrusions 22and bottom sections 23 in the top sheet 2A formed in the excretionhole-corresponding region, as shown in FIG. 12( a), or first protrusions21, second protrusions 22 and bottom sections 23 may not be formed inthe top sheet 2A in the regions on the outer sides of both edges in thewidthwise direction of the absorbent body and in the wing sections 5, asshown in FIG. 12( b). FIG. 13 is a schematic diagram showing a top sheetin an excretion hole-corresponding region as another modified example ofan absorbent article according to an embodiment of the invention. Also,openings 25B may be provided in the bottom sections 23B in the top sheet2B formed in the excretion hole-corresponding region, as shown in FIG.13, without being provided in the sides 26B of the first protrusions21B. Alternatively, openings may be formed in both sides and the bottomsections of the first protrusions in the top sheet formed in theexcretion hole-corresponding region. In such cases as well, it issufficient if the openings 25A, 25B and the modifying agent layers 24A,24B are provided at least in the excretion hole-corresponding region.

(3) So long as non-perforated regions are provided in the top sheet atleast on both sides in the widthwise direction of the perforated region,the section of the top sheet in which the non-perforated regions areprovided is not limited to the top sheet 2 in the absorbent article ofthe embodiment of the invention. This will still allow inhibition ofbody fluid that has exuded from the edges in the widthwise direction ofthe absorbent body, from exuding through the openings onto the surfaceof the top sheet in the region on the outer sides of both edges in thewidthwise direction of the absorbent body, when the absorbent article issubjected to pressure. For example, non-perforated regions may beprovided for the top sheet on both sides in the widthwise direction andon both sides in the lengthwise direction of the perforated region.

(4) The direction in which the first protrusions 21 extend is notlimited to the lengthwise direction so long as it is a prescribeddirection. FIG. 14 is a front view showing another modified example ofan absorbent article according to an embodiment of the invention. Thefirst protrusions 21C provided in the top sheet 2C may extend in thewidthwise direction (X direction), for example, as in the absorbentarticle 1C shown in FIG. 14. This will also reduce the contact areabetween the skin of the wearer and the top sheet 2, thus resulting in asatisfactory feel of the top sheet 2 on the skin.

(5) It is sufficient if the first protrusions 21 are provided in the topsheet at least in the excretion hole-corresponding region 16. In thiscase as well, the contact area between the skin of the wearer and thetop sheet 2 is reduced by the first protrusions 21 provided on the topsheet 2 in the excretion hole-corresponding region 16, and therefore thefeel of the top sheet 2 on the skin in the excretion hole-correspondingregion 16 is satisfactory. For example, the first protrusions may beprovided in the region 12 of the body section 10 in which the absorbentbody 4 is provided, and no first protrusions provided in the regions 14on the outer sides of both edges 41 in the widthwise direction of theabsorbent body 4 in the body section 10, or in the wing sections 5.

(6) The blood modifying agent layer 24 may be provided in the top sheet2 of the body section 10, in the regions 14 on the outer sides of bothedges 41 in the widthwise direction of the absorbent body 4. In thiscase as well, the blood modifying agent of the blood modifying agentlayer 24 functions as a lotion, and the blood modifying agent layer 24can reduce friction produced between the inner crotch of the wearer andthe edge sections of the absorbent article when the wearer is walking,for example.

EXAMPLES

According to the invention, the blood modifying agent has a mechanism oflowering the viscosity and surface tension of blood, and therefore bodyfluid migrates by the blood modifying agent layer 24 to the absorbentbody 4 without remaining in the top sheet 2, allowing it to be absorbedinto the absorbent body 4. In the following examples, the bloodmodifying agent was confirmed to have a mechanism of lowering theviscosity and surface tension of blood. This was confirmed using anonwoven fabric, which more readily retains body fluid than a resinfilm.

Example 1 Evaluation of Rewetting Rate and Absorbent Body Migration Rate[Data of Blood Modifying Agents]

A commercially available sanitary napkin was prepared. The sanitarynapkin was formed from a top sheet, formed of a hydrophilicagent-treated air-through nonwoven fabric (composite fiber composed ofpolyester and polyethylene terephthalate, basis weight: 35 g/m²), asecond sheet, formed of an air-through nonwoven fabric (composite fibercomposed of polyester and polyethylene terephthalate, basis weight: 30g/m²), an absorbent body comprising pulp (basis weight: 150-450 g/m²,increased at the center section), an acrylic super-absorbent polymer(basis weight: 15 g/m²) and tissue as a core wrap, a water-repellentagent-treated side sheet, and a back sheet composed of a polyethylenefilm.

The blood modifying agents used for the experiment are listed below.

[(a₁) Ester of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

UNISTAR H-408BRS, product of NOF Corp.

-   -   Tetrapentaerythritol 2-ethylhexanoate, weight-average molecular        weight: approximately 640

UNISTAR H-2408BRS-22, product of NOF Corp.

-   -   Mixture of tetrapentaerythritol 2-ethylhexanoate and        di-neopentyl 2-ethylhexanoate glycol (58:42, mass ratio),        weight-average molecular weight: approximately 520        [(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty        Acid]

Cetiol SB45DEO, Cognis Japan

-   -   Glycerin and fatty acid triester, with oleic acid or stearylic        acid as the fatty acid.

SOY42, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₁₄ fatty acid:C₁₆ fatty        acid:C₁₈ fatty acid:C₂₀ fatty acid (including both saturated        fatty acids and unsaturated fatty acids) at a mass ratio of        about 0.2:11:88:0.8, weight-average molecular weight: 880

Tri-C2L oil fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty        acid:C₁₂ fatty acid at a mass ratio of about 37:7:56,        weight-average molecular weight: approximately 570

Tri-CL oil fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₂ fatty        acid at a mass ratio of about 44:56, weight-average molecular        weight: approximately 570

PANACET 810s, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty        acid at a mass ratio of about 85:15, weight-average molecular        weight: approximately 480

PANACET 800, product of NOF Corp.

-   -   Glycerin and fatty acid triester with octanoic acid (C₈) as the        entire fatty acid portion, weight-average molecular weight:        approximately 470

PANACET 800B, product of NOF Corp.

-   -   Glycerin and fatty acid triester with 2-ethylhexanoic acid (C₈)        as the entire fatty acid portion, weight-average molecular        weight: approximately 470

NA36, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₁₆ fatty acid:C₁₈ fatty        acid:C₂₀ fatty acid (including both saturated fatty acids and        unsaturated fatty acids) at a mass ratio of about 5:92:3,        weight-average molecular weight: approximately 880

Tri-coconut fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty        acid:C₁₂ fatty acid:C₁₄ fatty acid:C₁₆ fatty acid (including        both saturated fatty acids and unsaturated fatty acids) at a        mass ratio of about 4:8:60:25:3, weight-average molecular        weight: 670

Caprylic acid diglyceride, product of NOF Corp.

-   -   Glycerin and fatty acid diester with octanoic acid as the fatty        acid, weight-average molecular weight: approximately 340        [(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty        Acid]

COMPOL BL, product of NOF Corp.

-   -   Dodecanoic acid (C₁₂) monoester of butylene glycol,        weight-average molecular weight: approximately 270

COMPOL BS, product of NOF Corp.

-   -   Octadecanoic acid (C₁₈) monoester of butylene glycol,        weight-average molecular weight: approximately 350

UNISTAR H-208BRS, product of NOF Corp.

-   -   Neopentylglycol di-2-ethylhexanoate, weight-average molecular        weight: approximately 360.        [(c₂) Ester of a Chain Hydrocarbon Tricarboxylic Acid, Hydroxy        Acid, Alkoxy Acid or Oxoacid with 3 Carboxyl Groups, and at        Least One Aliphatic Monohydric Alcohol]

Tributyl 0-acetylcitrate, product of Tokyo Kasei Kogyo Co., Ltd.

-   -   Weight-average molecular weight: approximately 400        [(c₃) Ester of a Chain Hydrocarbon Dicarboxylic Acid, Hydroxy        Acid, Alkoxy Acid or Oxoacid with 2 Carboxyl Groups, and at        Least One Aliphatic Monohydric Alcohol]

Dioctyl adipate, product of Wako Pure Chemical Industries, Ltd.

-   -   Weight-average molecular weight: approximately 380        [(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

ELECTOL WE20, product of NOF Corp.

-   -   Ester of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂),        weight-average molecular weight: approximately 360

ELECTOL WE40, product of NOF Corp.

-   -   Ester of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂),        weight-average molecular weight: approximately 390        [(e₁) Polyoxy C₂-C₆ Alkylene Glycol]

UNIOL D-1000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 1,000

UNIOL D-1200, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 1,160

UNIOL D-3000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 3,000

UNIOL D-4000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 4,000

UNIOL PB500, product of NOF Corp.

-   -   Polybutylene glycol, weight-average molecular weight:        approximately 500

UNIOL PB700, product of NOF Corp.

-   -   Polyoxybutylenepolyoxypropylene glycol, weight-average molecular        weight: approximately 700

UNIOL PB1000R, product of NOF Corp.

-   -   Polybutylene glycol, weight-average molecular weight:        approximately 1,000        [(e₂) Ester of a Polyoxy C₂-C₆ Alkylene Glycol and at Least One        Fatty Acid]

WILBRITE cp9, product of NOF Corp.

-   -   Polybutylene glycol compound with OH groups at both ends        esterified by hexadecanoic acid (C₁₆), weight-average molecular        weight: approximately 1,150        [(e₃) Ether of Polyoxy C₂-C₆ Alkylene Glycol and at Least One        Fatty Acid]

UNILUBE MS-70K, product of NOF Corp.

-   -   Stearyl ether of polypropylene glycol, approximately 15        repeating units, weight-average molecular weight: approximately        1,140        [(e₅) Ether of a Polyoxy C₂-C₆ Alkylene Glycol with Chain        Hydrocarbon Tetraol, Chain Hydrocarbon Triol or Chain        Hydrocarbon Diol]

UNILUBE 5TP-300 KB

-   -   Polyoxyethylenepolyoxypropylene pentaerythritol ether, produced        by addition of 5 mol of ethylene oxide and 65 mol of propylene        oxide to 1 mol of pentaerythritol, weight-average molecular        weight: 4,130

UNIOL TG-3000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        3,000

UNIOL TG-4000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        4,000        [(f₁) Chain Alkane]

PARLEAM 6, product of NOF Corp.

-   -   Branched hydrocarbon, produced by copolymerization of liquid        isoparaffin, isobutene and n-butene followed by hydrogen        addition, polymerization degree: approximately 5-10,        weight-average molecular weight: approximately 330

[Other Components]

NA50, product of NOF Corp.

-   -   Glycerin and fatty acid triester obtained by addition of        hydrogen to NA36 for reduced proportion of double bonds from        unsaturated fatty acid starting material, weight-average        molecular weight: approximately 880

(Caprylic acid/capric acid) monoglyceride, product of NOF Corp.

-   -   Glycerin and fatty acid monoester, with octanoic acid (C₈) and        decanoic acid (C₁₀) at a mass ratio of about 85:15,        weight-average molecular weight: approximately 220

Monomuls 90-L2 lauric acid monoglyceride, product of Cognis Japan

Isopropyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

-   -   Weight-average molecular weight: approximately 230

Diisostearyl malate

-   -   Weight-average molecular weight: approximately 640

UNIOL D-400, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 400

PEG1500, product of NOF Corp.

-   -   Polyethylene glycol, weight-average molecular weight:        approximately 1,500-1,600

NONION S-6, product of NOF Corp.

-   -   Polyoxyethylene monostearate, approximately 7 repeating units,        weight-average molecular weight: approximately 880

WILBRITE s753, product of NOF Corp.

-   -   Polyoxyethylenepolyoxypropylene polyoxybutylene glycerin,        weight-average molecular weight: approximately 960

UNIOL TG-330, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 6        repeating units, weight-average molecular weight: approximately        330

UNIOL TG-1000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        1,000

UNILUBE DGP-700, product of NOF Corp.

-   -   Diglyceryl ether of polypropylene glycol, approximately 9        repeating units, weight-average molecular weight: approximately        700

UNIOX HC60, product of NOF Corp.

-   -   Polyoxyethylene hydrogenated castor oil, weight-average        molecular weight: approximately 3,570

Vaseline, product of Cognis Japan

-   -   Petroleum-derived hydrocarbon, semi-solid

The IOBs, melting points and water solubilities of the samples are shownin Table 2.

The water solubility was measured by the method described above, andsamples that dissolved 24 hours after addition of 20.0 g to 100 g ofdesalted water were evaluated as “20 g<”, and samples of which 0.05 gdissolved in 100 g of desalted water but 1.00 g did not dissolve wereevaluated as 0.05-1.00 g.

For the melting point, “<45” indicates a melting point of below 45° C.

The skin contact surface of the top sheet of the sanitary napkin wascoated with the aforementioned blood modifying agent. Each bloodmodifying agent was used directly, when the blood modifying agent wasliquid at room temperature, or when the blood modifying agent was solidat room temperature it was heated to its melting point of +20° C., and acontrol seam HMA gun was used for atomization of the blood modifyingagent and coating onto the entire skin contact surface of the top sheetto a basis weight of about 5 g/m².

FIG. 15 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin (No. 2-5) wherein the top sheet comprisestri-C2L oil fatty acid glycerides. As clearly seen in FIG. 15, thetri-C2L oil fatty acid glycerides are present on the fiber surfaces asfine particulates.

In accordance with the above procedures, the rewetting rate and absorbermigration rate were measured. The results are shown below in Table 2.

[Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40mm×10 mm hole opened at the center) was placed on a top sheet comprisingeach blood modifying agent, and 3 g of horse EDTA blood at 37±1° C.(obtained by adding appropriate amount of ethylenediaminetetraaceticacid (hereunder, “EDTA”) to horse blood to prevent coagulation) wasdropped through the hole using a pipette (once), and after 1 minute, 3 gof horse EDTA blood at 37±1° C. was again added dropwise through theacrylic board hole with a pipette (twice).

After the second dropping of blood, the acrylic board was immediatelyremoved and 10 sheets of filter paper (Advantec Toyo Kaisha, Ltd,Qualitative Filter Paper No. 2, 50 mm×35 mm) were placed on the locationwhere the blood had been dropped, and then a weight was placed thereoverto a pressure of 30 g/cm². After 1 minute, the filter paper was removedand the “rewetting rate” was calculated by the following formula.

Rewetting rate (%)=100×(filter paper mass after test−initial filterpaper mass)/6

In addition to the rewetting rate evaluation, the “absorbent bodymigration rate” was also measured as the time until migration of bloodfrom the top sheet to the absorbent body after the second dropping ofblood. The absorbent body migration rate is the time from introducingthe blood onto the top sheet, until the redness of the blood could beseen on the surface and in the interior of the top sheet.

The results for the rewetting rate and absorbent body migration rate areshown below in Table 2.

Then the whiteness of the skin contact surface of the top sheet afterthe absorbent body migration rate test was visually evaluated on thefollowing scale.

VG (Very Good): Virtually no redness of blood remaining, and no cleardelineation between areas with and without blood.

G (Good): Slight redness of blood remaining, but difficult to delineatebetween areas with and without blood.

F (Fair): Slight redness of blood remaining, areas with blooddiscernible.

P (Poor): Redness of blood completely remaining.

The results are summarized below in Table 2.

TABLE 2 Water Weight- Absorber Blood modifying agent Melting solubilityaverage Rewetting migration Top sheet No. Type Product name IOB point (°C. ) (g) mol. wt. rate (%) rate (sec) whiteness 2-1 (A₁) UNISTARH-408BRS 0.13 <−5 <0.05 640 1.2 3 VG 2-2 UNISTAR H-2408BRS-22 0.18 <−5<0.05 520 2.0 3 VG 2-3 (A₂) CETIOL SB45DEO 0.16 44 <0.05 7.0 6 VG 2-4SOY42 0.16 43 <0.05 880 5.8 8 VG 2-5 Tri-C2L oil fatty acid glyceride0.27 37 <0.05 570 0.3 3 VG 2-6 Tri-CL oil fatty acid glyceride 0.28 38<0.05 570 1.7 3 VG 2-7 PANACET 810s 0.32 −5 <0.05 480 2.8 3 VG 2-8PANACET 800 0.33 −5 <0.05 470 0.3 3 VG 2-9 PANACET 800B 0.33 −5 <0.05470 2.0 3 VG 2-10 NA36 0.16 37 <0.05 880 3.9 5 VG 2-11 Tri-coconut fattyacid glyceride 0.28 30 <0.05 670 4.3 5 VG 2-12 Caprylic acid diglyceride0.58 <45 <0.05 340 4.2 9 G 2-13 (A₃) COMPOL BL 0.50 2 <0.05 270 2.0 5 G2-14 COMPOL BS 0.36 37 <0.05 350 7.9 9 G 2-15 UNISTAR H-208BRS 0.24 <−5<0.05 360 2.0 5 VG 2-16 (C₂) Tributyl O-acetylcitrate 0.60 <45 <0.05 4006.2 8 VG 2-17 (C₃) Dioctyl adipate 0.27 <45 <0.05 380 1.7 6 VG 2-18 (D₃)ELECTOL WE20 0.13 29 <0.05 360 1.8 5 VG 2-19 ELECTOL WE40 0.12 37 <0.05390 1.8 4 VG 2-20 (E₁) UNIOL D-1000 0.51 <45 <0.05 1,000 6.8 15 F 2-21UNIOL D-1200 0.48 <45 <0.05 1,160 0.5 11 F 2-22 UNIOL D-3000 0.39 <45<0.05 3,000 1.7 10 2-23 UNIOL D-4000 0.38 <45 <0.05 4,000 1.0 7 G 2-24(E₁) UNIOL PB500 0.44 <45 <0.05 500 4.5 4 G 2-25 UNIOL PB700 0.49 −5<0.05 700 2.8 5 G 2-26 UNIOL PB1000R 0.40 <45 <0.05 1,000 4.0 4 G 2-27(E₂) WILBRITE cp9 0.21 35 <0.05 1,150 1.4 3 G 2-28 (E₃) UNILUBE MS-70K0.30 <−10 <0.05 1,140 6.7 3 G 2-29 (E₅) UNILUBE 5TP-300KB 0.39 <45 <0.054,130 2.0 6 G 2-30 UNIOL TG-3000 0.42 <45 <0.05 3,000 0.8 6 G 2-31 UNIOLTG-4000 0.40 <45 <0.05 4,000 2.0 6 G 2-32 (F₁) PARLEAM 6 0.00 −5 <0.05330 6.0 8 VG 2-33 NA50 0.18 52 <0.05 880 15.5 60 P 2-34 (Caprylicacid/capric acid) monoglyceride 1.15 <45 20< 220 4.0 4 P 2-35 Monomuls90-L2 lauric acid monoglyceride 0.87 58 20< 6.2 7 P 2-36 Isopropylcitrate 1.56 <45 20< 230 12.2 5 G 2-37 Diisostearyl malate 0.28 <45 20<640 5.5 8 F 2-38 UNIOL D-400 0.76 <45 0.05<   400 8.7 40 P 2-39 PEG15000.78 40 20<  1,500- 11.0 38 P 1,600 2-40 NONION S-6 0.44 37 0.05<   8808.4 7 P 2-41 WILBRITE s753 0.67 −5 20< 960 9.3 9 F 2-42 UNIOL TG-3301.27 <45 0.05<  330 — — — 2-43 UNIOL TG-1000 0.61 <45 <0.05 1,000 14.2 7G 2-44 UNILUBE DGP-700 0.91 <0 0.05<  700 8.0 10 F 2-45 UNIOX HC60 0.4633 0.05-1.00 3,570 14.6 46 P 2-46 Vaseline 0.00 55 <0.05 9.7 10 F 2-47None — — — — 22.7  60< P

In the absence of a blood modifying agent, the rewetting rate was 22.7%and the absorbent body migration rate was greater than 60 seconds, butthe glycerin and fatty acid triesters all produced rewetting rates of nogreater than 7.0% and absorbent body migration rates of no longer than 8seconds, and therefore significantly improved the absorptionperformance. Of the glycerin and fatty acid triesters, however, no greatimprovement in absorption performance was seen with NA50 which had amelting point of above 45° C.

Similarly, the absorption performance was also significantly improvedwith blood modifying agents having an IOB of about 0.00-0.60, a meltingpoint of no higher than about 45° C. and a water solubility of nogreater than about 0.05 g in 100 g of water at 25° C. Rewetting rates ofno greater than 7.9% and absorbent body migration rates of no longerthan 15 seconds were achieved.

Next, several volunteer subjects were asked to wear sanitary napkinsNos. (2-1)-(2-47), and the obtained responses indicated that with thesanitary napkins comprising blood modifying agents Nos. (2-1)-(2-32),the top sheets had no sticky feel and the top sheets were smooth, evenafter absorption of menstrual blood

Also, with sanitary napkins Nos. (2-1)-(2-32), and particularly withsanitary napkins that comprised blood modifying agents Nos.(2-1)-(2-11), (2-15)-(2-19) and (2-32), the skin contact surfaces of thetop sheets after absorption of menstrual blood had not been reddened bythe blood and the unpleasantness was minimal.

Example 2

The rewetting rate was evaluated for blood from different animals inaccordance with the above procedures. The following blood was used forthe test.

[Animal Species]

(1) Human

(2) Horse

(3) Sheep

[Types of Blood]

Defibrinated blood: blood sampled and agitated together with glass beadsin an Erlenmeyer flask for approximately 5 minutes.

EDTA blood: 65 mL of venous blood with addition of 0.5 mL of a 12%EDTA·2K isotonic sodium chloride solution.

[Fractionation]

Serum or blood plasma: Supernatant obtained after centrifugation ofdefibrinated blood or EDTA blood for 10 minutes at room temperature atabout 1900 G.

Blood cells: Obtained by removing the serum from the blood, washingtwice with phosphate buffered saline (PBS), and adding phosphatebuffered saline to the removed serum portion.

An absorbent article was produced in the same manner as Example 2,except that the tri-C2L oil fatty acid glyceride was coated at a basisweight of about 5 g/m², and the rewetting rate of each of theaforementioned blood samples was evaluated. Measurement was performed 3times for each blood sample, and the average value was recorded.

The results are shown in Table 3 below.

TABLE 3 Rewetting rate (%) With blood Without blood Animal modifyingmodifying No. species Type of blood agent agent 1 Human Defibrinatedblood 1.6 5.0 2 Defibrinated serum 0.2 2.6 3 Defibrinated blood cells0.2 1.8 4 EDTA blood 2.6 10.4 5 EDTA plasma 0.0 5.8 6 EDTA blood cells0.2 4.3 7 Horse Defibrinated blood 0.0 8.6 8 Defibrinated serum 0.2 4.29 Defibrinated blood cells 0.2 1.0 10 EDTA blood 6.0 15.7 11 EDTA plasma0.1 9.0 12 EDTA blood cells 0.1 1.8 13 Sheep Defibrinated blood 0.2 5.414 Defibrinated serum 0.3 1.2 15 Defibrinated blood cells 0.1 1.1 16EDTA blood 2.9 8.9 17 EDTA plasma 0.0 4.9 18 EDTA blood cells 0.2 1.6

The same trend was seen with human and sheep blood as with the horseEDTA blood, as obtained in Example 2. A similar trend was also observedwith defibrinated blood and EDTA blood.

Example 3 Evaluation of Blood Retention

The blood retention was evaluated for a top sheet comprising a bloodmodifying agent and a top sheet comprising no blood modifying agent.

[Test Methods]

(1) A tri-C2L oil fatty acid glyceride was atomized on the skin contactsurface of a top sheet formed from an air-through nonwoven fabric(composite fiber composed of polyester and polyethylene terephthalate,basis weight: 35 g/m²), using a control seam HMA gun, for coating to abasis weight of about 5 g/m². For comparison, there was also prepared asheet without coating with the tri-C2L oil fatty acid glyceride. Next,both the tri-C2L oil fatty acid glyceride-coated top sheet and thenon-coated top sheet were cut to a size of 0.2 g, and the mass (a) ofthe cell strainer+top sheet was precisely measured.

(2) After adding about 2 mL of horse EDTA blood from the skin contactsurface side, it was allowed to stand for 1 minute.

(3) The cell strainer was set in a centrifuge tube, and subjected tospin-down to remove the excess horse EDTA blood.

(4) The mass (b) of the top sheet containing the cell strainer+horseEDTA blood was measured. (5) The initial absorption (g) per 1 g of topsheet was calculated by the following formula.

Initial absorption=[mass(b)×mass(a)]/0.2

(6) The cell strainer was again set in the centrifuge tube andcentrifuged at room temperature for 1 minute at approximately 1,200 G.

(7) The mass (c) of the top sheet containing the cell strainer+horseEDTA blood was measured.

(8) The post-test absorption (g) per 1 g of top sheet was calculated bythe following formula.

Post-test absorption=[mass(c)−mass(a)]/0.2

(9) The blood retention (%) was calculated according to the followingformula.

Blood retention (%)=100×post-test absorption/initial absorption

The measurement was conducted 3 times, and the average value wasrecorded.

The results are shown in Table 4 below.

TABLE 4 Blood retention (%) With blood Without blood modifying agentmodifying agent Horse EDTA blood 3.3 9.2

The top sheets comprising blood modifying agents had low bloodretentions, suggesting that blood rapidly migrated into the absorbentbody after absorption.

Example 4 Viscosity of Blood Containing Blood Modifying Agent

The viscosity of the blood modifying agent-containing blood was measuredusing a Rheometric Expansion System ARES (Rheometric Scientific, Inc.).After adding 2 mass % of PANACET 810s to horse defibrinated blood, themixture was gently agitated to form a sample, the sample was placed on a50 mm-diameter parallel plate, with a gap of 100 μm, and the viscositywas measured at 37±0.5° C. The sample was not subjected to a uniformshear rate due to the parallel plate, but the average shear rateindicated by the device was 10 s⁻¹.

The viscosity of the horse defibrinated blood containing 2 mass %PANACET 810s was 5.9 mPa·s, while the viscosity of the horsedefibrinated blood containing no blood modifying agent was 50.4 mPa·s.Thus, the horse defibrinated blood containing 2 mass % PANACET 810sclearly had an approximately 90% lower viscosity than the bloodcontaining no blood modifying agent.

It is known that blood contains components such as blood cells and hasthixotropy, and it has been found that the blood modifying agent of thisdisclosure can lower blood viscosity in the low viscosity range.Lowering the blood viscosity presumably allows absorbed menstrual bloodto rapidly migrate from the top sheet to the absorbent body.

Example 5 Photomicrograph of Blood Modifying Agent-Containing Blood

Menstrual blood was sampled from healthy volunteers onto Saran wrap, andPANACET 810s dispersed in a 10-fold mass of phosphate-buffered salinewas added to a portion thereof to a PANACET 810s concentration of 1 mass%. The menstrual blood was dropped onto a slide glass, a cover glass wasplaced thereover, and the state of the erythrocytes was observed with anoptical microscope. A photomicrograph of menstrual blood containing noblood modifying agent is shown in FIG. 16( a), and a photomicrograph ofmenstrual blood containing PANACET 810s is shown in FIG. 16( b).

As shown FIG. 16, it is seen that the erythrocytes formed aggregatessuch as rouleaux in the menstrual blood containing no blood modifyingagent, while the erythrocytes were stably dispersed in the menstrualblood containing PANACET 810s. This suggests that the blood modifyingagent functions to stabilize erythrocytes in blood.

Example 6 Surface Tension of Blood Containing Blood Modifying Agent

The surface tension of blood containing a blood modifying agent wasmeasured by the pendant drop method, using a Drop Master500 contactangle meter by Kyowa Interface Science Co., Ltd. The surface tension wasmeasured after adding a prescribed amount of blood modifying agent tosheep defibrinated blood, and thoroughly shaking. The measurement wasaccomplished automatically with a device, and the surface tension γ wasdetermined by the following formula (see FIG. 17).

γ=g×ρ×(de)²×1/H

g: Gravitational constant

1/H: Correction factor determined from ds/de

ρ: Density

de: Maximum diameter

ds: Diameter at location of increase by de from dropping edge

The density ρ was measured at the temperatures listed in Table 5,according to JIS K 2249-1995, “Density test methods anddensity/mass/volume conversion tables”, “5. Vibrating density testmethod”.

The measurement was accomplished using a DA-505 by Kyoto ElectronicsCo., Ltd.

The results are shown in Table 5 below.

TABLE 5 Blood modifying agent Amount Measuring Surface tension No. Type(mass %) temperature (° C.) (mN/m) 1 — — 35 62.1 2 PANACET 0.01 35 61.53 810s 0.05 35 58.2 4 0.10 35 51.2 5 ELECTOL 0.10 35 58.8 WE20 6 PARLEAM6 0.10 35 57.5 7 — — 50 56.3 8 WILBRITE 0.10 50 49.1 cp9

Table 5 shows that the blood modifying agent can lower the surfacetension of blood despite its very low solubility in water, as seen by awater solubility of about 0.00-about 0.05 g in 100 g of water at 25° C.

Lowering the surface tension of blood presumably allows absorbed bloodto rapidly migrate from the top sheet to the absorbent body, withoutbeing retained between the top sheet fibers.

Any of the aforementioned embodiments may also be applied in combinationwith the modifications. The modifications may also be applied incombination with each other.

The explanation above is merely for illustration, and the invention isin no way restricted by the described embodiment.

EXPLANATION OF SYMBOLS

-   1, 1C Absorbent articles-   2, 2A, 2B, 2C Top sheets-   3 Back sheet-   4 Absorbent body-   5 Wing section-   6 Pressure-sensitive adhesive section-   7 Compressed groove-   8 Seal section-   10 Body section-   16 Excretion hole-corresponding region-   21, 21B, 21C First protrusions-   22 Second protrusion-   23, 23B Bottom sections-   24, 24A, 24B Blood modifying agent layers-   25, 25A, 25B Openings-   26, 26B First protrusion sides-   100 Top sheet production apparatus-   120 Pattern drum-   130 Embossing apparatus-   140 Back sheet roll-   150 Cutter-   160 Modifying agent-coating sprayer-   210 Resin film sheet roll-   212, 214, 216 Resin film sheets-   220 Recess-forming roll-   230 Stretching gear roll-   231 Upper roll-   232 Lower roll-   233,235 Gear teeth-   234 Interrupted location of gear teeth

1. An absorbent article having a lengthwise direction and a widthwisedirection, and comprising a top sheet provided on the skin side, aliquid-impermeable back sheet provided on the clothing side, and aliquid-retaining absorbent body provided between the top sheet and theback sheet, wherein the top sheet is a resin sheet having perforatedregions in which openings are formed and non-perforated regions in whichopenings are not formed, the perforated regions being provided at leastin the excretion hole-corresponding region that corresponds to theexcretion hole for body fluid of the wearer, the top sheet having ablood modifying agent layer on the surface of at least the excretionhole-corresponding region, and the blood modifying agent in the bloodmodifying agent layer having an IOB of 0 to 0.60, a melting point of nohigher than 45° C. and a water solubility of no greater than 0.05 g in100 g of water at 25° C.
 2. The absorbent article according to claim 1,wherein the non-perforated regions are provided at least on both sidesin the widthwise direction of the perforated region.
 3. The absorbentarticle according to claim 1, wherein the top sheet comprises, in atleast the excretion hole-corresponding region, a plurality ofprotrusions that extend in one direction and are aligned in thedirection perpendicular to that direction, and bottom sections at thesections that are to constitute the bases of the protrusions.
 4. Theabsorbent article according to claim 3, wherein the one direction is thelengthwise direction, and the top sheet further comprises the pluralityof protrusions on the outer sides of both edges in the widthwisedirection of the absorbent body.
 5. The absorbent article according toclaim 3, wherein the top sheet further comprises the blood modifyingagent layer on the outer sides of both edges in the widthwise directionof the absorbent body.
 6. The absorbent article according to claim 3,which further comprises, between adjacent protrusions, diagonalprotrusions that extend in a direction diagonal to the one direction. 7.The absorbent article according to claim 3, wherein the openings areprovided on the sides of the protrusions.
 8. The absorbent articleaccording to claim 1, wherein the blood modifying agent is selected fromthe group consisting of the following items (i)-(iii), and anycombination thereof: (i) a hydrocarbon; (ii) a compound having (ii-1) ahydrocarbon moiety, and (ii-2) one or more groups each selected from thegroup consisting of carbonyl group (—CO—) and oxy group (—O—) insertedbetween a C—C single bond of the hydrocarbon moiety; and (iii) acompound having (iii-1) a hydrocarbon moiety, (iii-2) one or more groupseach selected from the group consisting of carbonyl group (—CO—) and oxygroup (—O—) inserted between a C—C single bond of the hydrocarbonmoiety, and (iii-3) one or more groups each selected from the groupconsisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting a hydrogen of the hydrocarbon moiety; wherein when 2 ormore oxy groups are inserted in the compound of (ii) or (iii), the oxygroups are not adjacent.
 9. The absorbent article according to claim 1,wherein the blood modifying agent is selected from the group consistingof the following items (i′)-(iii′), and any combination thereof: (i′) ahydrocarbon; (ii) a compound having at least (ii′-1) a hydrocarbonmoiety, and (ii′-2) one or more bonds each selected from the groupconsisting of carbonyl bond (—CO—), at least one ester bond (—COO—), atleast one carbonate bond (—OCOO—), and at least one ether bond (—O—)inserted between a C—C single bond of the hydrocarbon moiety; and (iii)a compound having at least (iii′-1) a hydrocarbon moiety, (iii′-2) oneor more bonds each selected from the group consisting of carbonyl bond(—CO—), at least one ester bond (—COO—), at least one carbonate bond(—OCOO—), and at least one ether bond (—O—) inserted between a C—Csingle bond of a hydrocarbon moiety, and (iii′-3) one or more groupseach selected from the group consisting of carboxyl group (—COOH) andhydroxyl group (—OH) substituting a hydrogen on the hydrocarbon moiety;wherein when 2 or more same or different bonds are inserted in thecompound of (ii) or (iii′), the bonds are not adjacent.
 10. Theabsorbent article according to claim 1, wherein the blood modifyingagent is selected from the group consisting of the following items(A)-(F), and any combination thereof: (A) an ester of (A1) a compoundhaving a chain hydrocarbon moiety and 2-4 hydroxyl groups substitutinghydrogens on the chain hydrocarbon moiety, and (A2) a compound having achain hydrocarbon moiety and 1 carboxyl group substituting a hydrogen onthe chain hydrocarbon moiety; (B) an ether of (B1) a compound having achain hydrocarbon moiety and 2-4 hydroxyl groups substituting hydrogenson the chain hydrocarbon moiety and (B2) a compound having a chainhydrocarbon moiety and 1 hydroxyl group substituting a hydrogen on thechain hydrocarbon moiety; (C) an ester of (C1) a carboxylic acid,hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbonmoiety and 2-4 carboxyl groups substituting hydrogens on the chainhydrocarbon moiety and (C2) a compound having a chain hydrocarbon moietyand 1 hydroxyl group substituting a hydrogen on the chain hydrocarbonmoiety; (D) a compound having a chain hydrocarbon moiety and one bondselected from the group consisting of an ether bond (—O—), carbonyl bond(—CO—), ester bond (—COO—) and carbonate bond (—OCOO—) inserted betweena C—C single bond of the chain hydrocarbon moiety; (E) a polyoxy C₂-C₆alkylene glycol, or alkyl ester or alkyl ether thereof; and (F) a chainhydrocarbon.
 11. The absorbent article according to claim 1, wherein theblood modifying agent is selected from the group consisting of (a₁)esters of chain hydrocarbon tetraols and at least one fatty acid, (a₂)esters of chain hydrocarbon triols and at least one fatty acid, (a₃)esters of chain hydrocarbon diols and at least one fatty acid, (b₁)ethers of chain hydrocarbon tetraols and at least one aliphaticmonohydric alcohol, (b₂) ethers of chain hydrocarbon triols and at leastone aliphatic monohydric alcohol, (b₃) ethers of chain hydrocarbon diolsand at least one aliphatic monohydric alcohol, (c₁) esters of chainhydrocarbon tetracarboxylic acids, hydroxy acids, alkoxy acids oroxoacids with 4 carboxyl groups, and at least one aliphatic monohydricalcohol, (c₂) esters of chain hydrocarbon tricarboxylic acids, hydroxyacids, alkoxy acids or oxoacids with 3 carboxyl groups, and at least onealiphatic monohydric alcohol, (c₃) esters of chain hydrocarbondicarboxylic acids, hydroxy acids, alkoxy acids or oxoacids with 2carboxyl groups, and at least one aliphatic monohydric alcohol, (d₁)ethers of aliphatic monohydric alcohols and aliphatic monohydricalcohols, (d₂) dialkyl ketones, (d₃) esters of fatty acids and aliphaticmonohydric alcohols, (d₄) dialkyl carbonates, (e₁) polyoxy C₂₋C₆alkylene glycols, (e₂) esters of polyoxy C₂₋C₆ alkylene glycols and atleast one fatty acid, (e₃) ethers of polyoxy C₂₋C₆ alkylene glycols andat least one aliphatic monohydric alcohol, (e₄) esters of polyoxy C₂₋C₆alkylene glycols with chain hydrocarbon tetracarboxylic acids, chainhydrocarbon tricarboxylic acids or chain hydrocarbon dicarboxylic acids,(e₅) ethers of polyoxy C₂₋C₆ alkylene glycols with chain hydrocarbontetraols, chain hydrocarbon triols or chain hydrocarbon diols, and (f₁)chain alkanes.